the perimeter of equilateral triangle is 21m. Find the area. Using Heron's Formula


plzzz answer fast i will mark brainliest.

Answers

Answer 1

Answer:

A ≈ 21.22 m²

Step-by-step explanation:

The area (A) of a triangle using Heron's formula is

A = [tex]\sqrt{s(s-a)(s-b)(s-c)}[/tex]

where s is the semi perimeter and a, b, c the sides of the triangle.

Here the perimeter of the equilateral triangle is 21 m , then

a = b = c = 21 ÷ 3 = 7 m

s = 21 ÷ 2 = 10.5

Then

A = [tex]\sqrt{10.5(10.5-7)(10.5-7)(10.5-7)}[/tex]

   = [tex]\sqrt{10.5(3.5)(3.5)(3.5)}[/tex]

   = [tex]\sqrt{450.1875}[/tex]

   ≈ 21.22 m² ( to 2 dec. places )


Related Questions

[tex]2 \sqrt{75} - \sqrt{108} + 5 \sqrt{48}[/tex]

Answers

[tex]\\ \sf\longmapsto 2 \sqrt{75} - \sqrt{108} + 5 \sqrt{48} \\\\ \sf\longmapsto 2 \sqrt{25 \times 3} - \sqrt{36 \times 3} + 5 \sqrt{16 \times 3} \\ \\ \sf\longmapsto 2 \times 5 \sqrt{3} - 6 \sqrt{3} + 5 \times 4 \sqrt{3} \\ \\ \sf\longmapsto 10 \sqrt{3} - 6 \sqrt{3} + 20 \sqrt{3} \\ \\ \sf\longmapsto (10 - 6 + 20) \sqrt{3} \\ \\ \sf\longmapsto 24 \sqrt{3} [/tex]

Answer:

24aprtment3

Step-by-step explanation:

Solve for x:
( x - 6 ) ^ 2 = 7

Answers

Answer: x= 6 +/- root of 7

Step-by-step explanation:

1. Expand the left hand side: e.g, 3^2 = 3×3 =9

(x-6)(x-6) = 7

2. Multiply the brackets first by "separating" one of them, and take 7 to the left hand side:

x(x-6) - 6(x-6) =7

x^2 - 6x -6x +36-7=0

Simplify by adding like terms

x^2 -12x +29=0

3.Now your equation is in the form ax^2+bx + c =0, it means you can use the quadratic formula which is x= [-b +/- root of (b^2 - 4ac)]÷ 2a

Then SUBSTITUTE where:

a=1

b= -12

c=29

Therefore, x should be 6+ root of 7 OR 6- root of 7

Answer:

uhhhh okay thank you for removing my answer

Step-by-step explanation:

kendra is 3 times her dauters age plus 7 years kendra is 49 years old. write an equation to find he duaghters age?

Answers

Answer:

3x+ 7 =49

Step-by-step explanation:

49-7= 42

42 divided by 3 = 14

her daughter is 14 years old

I truly hope this helped, it makes sense to me. I wasn't sure whether or not you needed a more detailed equation, but that's one.

have a great day!

Daisy (5,9,2,6,14,3)
Milkweed (10,8,22,12,12,9)
Coneflower (3,7,2,10,16,7)
A biology class took a field trip. The students counted the number of daisy, milkweed, and coneflower plants in six different locations. The data sets are shown above. What is the overall range in the number of plants for all three types of plants?

Answers

Answer:

The overall range is 20

Step-by-step explanation:

Given

The above dataset

Required

The overall range

Range is calculated as

[tex]Range = Highest - Lowest[/tex]

The highest of the dataset is 22, and it can be found in  Milkweed.

The lowest of the dataset is 2, and it can be found in  Daisy

So, the range is:

[tex]Range = 22 - 2[/tex]

[tex]Range = 20[/tex]

5×12÷[-12÷{15+(4-3)}]​

Answers

Answer:   -80

Step-by-step explanation:

D.2 please help I’ll mark brainliest

Answers

Answer:

At 2

Step-by-step explanation:

I think it is because it slants down instead of going up. That is the reason why I say my answer is at 2.

HOPE THIS HELPED

secA-tanA=(cosA/2-sinA/2)/(cosA/2+sinA/2)​

Answers

Answer:

Step-by-step explanation:

SecA - TanA

= 1/CosA - SinA/CosA

= 1 - SinA/CosA

We know that Sin2A = 2SinACosA  and Cos2A = Cos²A - Sin²A

Thus SinA = Sin2(A/2) = 2Sin(A/2)CosA/2

       CosA = Cos2(A/2) = Cos²A/2 - Sin²A/2

Now substituting the values back,

=> 1 - 2Sin(A/2)Cos(A/2) / Cos²(A/2) - Sin²(A/2)

// we know that Sin²θ + Cos²θ = 1

=> Sin²(A/2) + Cos²A/2 -  2Sin(A/2)Cos(A/2) / Cos²(A/2) - Sin²(A/2)

//We know that numerator is of form a² + b² - 2ab which is (a - b)².

//Similarly denominator is of form a² - b² which is (a - b)(a + b)

=> [Sin(A/2) - Cos(A/2)]² / [Cos(A/2) + Sin(A/2)][Cos(A/2) - Sin(A/2)]

=> [ - {Cos(A/2) - Sin(A/2)}]² / [Cos(A/2) + Sin(A/2)][Cos(A/2) - Sin(A/2)]

=> [Cos(A/2) - Sin(A/2)]² /  [Cos(A/2) + Sin(A/2)][Cos(A/2) - Sin(A/2)]

=> [Cos(A/2) - Sin(A/2)] / [Cos(A/2) + Sin(A/2)]

= R.H.S

Hence proved.

x2 +15-8x entre 3-x ayuda pliz

Answers

By using Pythagorean theorem or just guesswork, we can see that: (x-3)(x-5) = 0, so the roots of the equation are x = 3, 5.

*HELP*
calculate the pay for the following day of a weekly time card given a wage of $12 an hour

Answers

Answer:

96 dollars and 50 cents

Step-by-step explanation:

State the equation, in slope-intercept form, of each of the following graphs of linear relations.
Explain how the equation was determined.



Answers

Answer: y=80/5x+80

Step-by-step explanation:

At one point graph goes from (0,400) to (25,800). So the y intercept is 400 because that’s where the line was at x=0. 0 to 25 is 25. 400 to 800 is 400. So the equation would be y=400/25x+400. But you can divide all of it by 5 to get y=80/5x+80.

(PICTURE) 15 Points and marking Brainliest could someone please answer/explain this for me

Answers

Answer:

9. Hypotenuse = √(19.1²+11.3²) = √492.5 = 22.2 m²

10. Area = (34×40)/2 + (17²×π/2)

= 680 + 453.96

= 1133.96 cm²

Answered by GAUTHMATH

A 16-ounce package of frozen peas costs
85¢. Give the unit price in cents per ounce. Round to the nearest tenth of a cent.

The peas cost ___ cents per ounce.

Note: Rounding to the nearest tenth of a cent is the same as rounding to the nearest thousandth of a dollar.

Answers

Answer:

5.3 cents

Step-by-step explanation:

85/16

because all 16 ounces cost 85 cents

Answer:

5.3 cents.

Step-by-step explanation:

Find the area of the regular polygon. Round your answer to the nearest hundredth.

Answers

Answer:

Step-by-step explanation:

The central angle of a hexagon is 60 degrees. Drop a line from the center to the middle of the side marked 7.

Use the  tan of the angle so formed (which is 30 degrees)

Tan(30)= opposite / height (which is the line you just drew).

Tan(30) = 3.5 / h

Tan(30) = 0.5774

Tan(30) = 3.5 / h                multiply both sides by h

h*Tan(30) = 3.5                  Divide by tan30

h = 3.5 / Tan(30)

h = 3.5 / 0.5774

h = 6.062

Now from both ends of the given side, draw 2 lines to the center. Find the area of that triangle.

Area of 1 triangle = 1/2 * b * h

area of 1 triangle = 1/2 * 7 * 6.062

Area of 1 triangle = 21.2176

There are 6 such triangles so multiply that number by 6

Answer:  6 * 21.2176

Answer:  127.31

Nia solved the equation -1.98 = 5.2v + 13.1. Her answer was v = -2.9. She is fairly confident about her answer, but wants to do a quick check of her solution using estimation to make sure her answer is reasonable.

Which of the following shows a good check of her answer?

Answers

Answer:

substitute for v, when v = -2.9

Step-by-step explanation:

[tex]-1.98=5.2v+13.1[/tex]

subtract 13.1 on both sides.

[tex]-15.08=5.2v[/tex]

divide by 5.2 to isolate v

[tex]\frac{-15.08}{5.2} = \frac{5.2v}{5.2}[/tex]

[tex]-2.9=v[/tex]

substitute for v

[tex]-1.98=5.2(-2.9)+13.1[/tex]

[tex]-1.98=-15.08+13.1[/tex]

[tex]-1.98=-1.98[/tex]

ASAP!! can i get help on this one and can i please get a vivid explanation thank you.

Answers

Answer:

3x + 11

Step-by-step explanation:

1) Remove Parentheses:

x + 4 + 2x + 7

2) Combine Like Terms:

(2x + x) and (4 + 7)

3) Simplify:

3x + 11

Hope this helps, good luck! Have a good day. :)

Marking brainliest please explain if you can (PICTURE)

Answers

Answer:

Anyone???

Step By Step
I think it’s because James is using only 18 m of wood, and only whole numbers. With only whole numbers, there are no more factors of 18 that would make sense for a picture frame, and the maximum area has been found with the dimensions of 6 and 3. If he continues the chart and goes higher than 20 (let alone 18), it would be pointless since he wants to make a frame with 18 m of wood.

QUESTION 2 Write the slope-intercept form of the equation of the line through the gran point micia the grea slope through: (5,-2), siope--1 Oay=-2=6 Oby=-2-3 O cy=-x=3 Ody=-z-6​

Answers

Answer:

y = -x+3

Step-by-step explanation:

Slope intercept form of a line is

y = mx+b where m is the slope and b is the y intercept

y = -1x +b

Using the point for x and y we can calculate b

-2 = -1(5)+b

-2 = -5+b

Add 5 to each side

-2+5 = b

3 = b

y = -x+3

The two bases of a trapezoid measure 14 inches and 10 inches respectively. The trapezoid's height is 8 inches. What is the area of the trapezoid?
192 square inches

1120 square inches

140 square inches

96 square inches

Answers

Answer:

A = 96 inches ^2

Step-by-step explanation:

The area of a trapezoid is given by

A = 1/2 ( b1+b2)h  where b1 and b2 are the bases and h is the height

A = 1/2( 14+10)*8

A = 1/2(24)*8

A = 12*8

A = 96 inches ^2

[tex]\huge\mathfrak\red{❥︎ANSWER}[/tex]

A = 96 square inches..

Step-by-step explanation:

The area of trapezoid is given

A = 1/2 (b1+b2)h where b1 and b2 is base and h is height

A = 1/2 (14+10)*8

A = 1/2 (24)*8

A = 12 * 8

A = 96 square inches ....

ANSWER QUICK !!
Yuri is participating in a tund-raiser at school. She will receive donations from 2 people. A cousin will donate $0.40 for every 1/8 mile that Yuri walks.
A friend will give Yuri a one-time donation of $30
What is the minimum number of miles Yuri needs to walk to raise at least $507 Enter the answer in the box,

Answers

507 - 30 =  477

477 / 0.4 = 1192.5

1192.4 / 8 = 149.0625 miles or 150 miles

i don't know if this is right cause the answer seems so absurd

Your best friend made 60% of the 40 shots he took. how many shots did your friend make?​

Answers

Answer:

24

Step-by-step explanation:

We need to find 60% of 40

60% * 40

.60 *40

24

He makes 24 shots

Step-by-step explanation:

60%/100%×40

60%/10%×4 (0 is cancelled)

6×4 (60 and 10 Cancelled)

24 Answer

What is 51809 rounded to 1,2 and 3 significant figures?
PLSS HELP​

Answers

Answer:

1 significant figure: 50,000 2 significant figures: 52,000 3 significant figures: 51,800

Step-by-step explanation:

FIrst, a significant figure is basically a non-zero digit (at least in your case). Basically, the 1 significant figure in your case would be to the nearest 10 thousand, which would be 50,000. Now, for 2 significant figures. This would be the nearest thousand, 52,000. Finally, 3 significant figures is to the nearest hundred, aka 51,800. Note: If you find a problem like this again 0 in between two digits that aren't 0 is a significant digit, aka the 0 in 51809. Hope this helped!

Solve the inequality: (x −3)12+ 2 ≥4
Question 14 options:

A)

x ≥ 35

B)

x ≥ 13

C)

x ≥ 11

D)

x ≥ 7

Answers

The answer should be C! If you move everything that is not x to the right, you will get x is greater than or equal to 11

Answer:

Its c

Step-by-step explanation:

It takes four or three hours to get a pair of socks and seven hours to get a pair of clothes as he spends 89 hours kidding a total of 15 pairs of socks and gloves how many pairs of each does she kinit?

Answers

Answer:

Gloves = 11 pairs

Socks = 4 pairs

Step-by-step explanation:

Given that :

Time taken to knit pair of socks = 3 hours

Time taken to knit pair of gloves = 7 hours

Total time taken to knit 15 pairs of gloves and socks = 89 hours

Let :

number of socks = x and number of gloves = y

x + y = 15 - - - - (1)

3x + 7y = 89 - - - (2)

From (1):

x = 15 - y

Put x = 15 - y in (2)

3(15 - y) + 7y = 89

45 - 3y + 7y = 89

45 + 4y = 89

4y = 89 - 45

4y = 44

y = 44/4

y = 11

From :

x = 15 - y

x = 15 - 11

x = 4

How many solutions does 6 - 3x = 4 - X-3 - 2x have?
O A. Infinitely many solutions
O B. No solutions
C. Two solutions
D. One solution

Answers

Answer:

6 - 3x = 4 - X-3 - 2x

-3x+x+2x=4-6-3

0x=-5

No solutions

Write the equation of the line that passes through the points (−4,1) and (−9,5). Put your answer in fully reduced point-slope form, unless it is a vertical or horizontal line.

Help plz

Answers

Step-by-step explanation:

gradient(m)=change in y/change in x

=5-1/-9-(-4)

=4/-9+4

=4/-5

equation now

y-y1=m(x-x1)

y-1=4/-5[x-(-4)]

y=4/-5(x+4)+1

y=-4/5x-16/5+1

y=-4/5x-21/5

Answer:

y = -4/5x - 11/5

Step-by-step explanation:

First, find the slope using the slope formula.

[tex]m=\frac{y_1-y_2}{x_1-x_2}\\\\m=\frac{1-5}{-4-(-9)}\\\\m=-\frac{4}{5}[/tex]

Then, use the point-slope formula and substitute the values for the variables. I'll use (-4, 1) in this instance.

[tex]y-y_1=m(x-x_1)\\\\y-1=-\frac{4}{5}(x+4)\\\\y-1=-\frac{4}{5}x-\frac{16}{5}\\\\y=-\frac{4}{5}x-\frac{11}{5}[/tex]

Hello!! Please help me ASAP
Using special right triangles show and explain all work for each problem. Each solution and work should demonstrate your understanding of Special Right Triangles (30-60-90 and 45-45-90)
Find the missing side length and angle of this triangle. I've attached the triangle.

Answers

Answer:

Step-by-step explanation:

The basic 30-60-90 triangle ratio is:

Side opposite to 30° angle is : x

Side opposite to 60° angle is : x √3

Side opposite to 90° angle is : 2x

From the diagram we learn that

x√3 = 10

[tex]x = \frac{10}{\sqrt{3}}=\frac{10*\sqrt{3} }{\sqrt{3}*\sqrt{3}}\\\\x=\frac{10\sqrt{3}}{3}= 5.77\\[/tex]

∠T = 30°, Side opposite to ∠T is AC = 5.77

∠A = 90°, side opposite to ∠A is TC = 2x = 2*5.77 = 11.54

Within 9 hours, the number of stars seen went from 190 to 33 as the sun started to rise. Find out how many stars are getting hidden by the sunlight each hour.

Answers

Answer:

Approximately 17 stars

which of the following represents x= 1/2 y written in general form?

Answers

Answer:  Choice C

2x-y = 0

=============================================

Work Shown:

x = (1/2)y

2x = y ... multiply both sides by 2

2x-y = 0 ... subtract y from both sides

This is in standard form Ax+By = C, where A,B,C are integers. In this case, A = 2, B = -1, C = 0.

I'LL GIVE BRAINLIEST !!! FASTER

please explain how do you get the answer !​

Answers

Answer:

70

Step-by-step explanation:

we have the angle of vertex in the isosceles triangle = 180-2*bottom coner= 180-65/2=50

3 angles in the equilateral triangle are equal to 60

we have 50 + 60 +h =the angle of PQR =180

h=70

Answer: h = 70°

In the triangle with Angle R = 65

It is a isoceles triangle as two sides are equal

So base angles will be equall too

Then the third angle will which is the q one will be

65+65+q = 180

q = 180 - 130

q = 50

In the other triangle with all sides equal will be equilateral triangle which means all angles equal = 60

So

Now ATQ

60 + 50 + h = 180

h = 180 - 110 (Angles on a straight line adds upto 180)

h = 70

Must click thanks and mark brainliest

Lúc 6 giờ, một ô tô xuất phát từ A đến B với vận tốc trung bình 40km/h. Khi đến B,

người lái xe làm nhiệm vụ giao nhận hàng trong 30 phút rồi cho xe quay trở về A với vận

tốc trung bình 30km/h. Tính quãng đường AB, biết rằng ô tô về đến A lúc 10 giờ cùng

ngày.

Answers

Answer:

Đáp án:

60km

Step-by-step explanation:

30 phút

=

1

2

giờ

Ô tô đi từ A đến B rồi từ B về A mất số thời gian là:

10

6

1

2

=

3

,

5

giờ (không tính thời gian nhận hàng)

Gọi độ dài quãng đường AB là

x

(km)

Ta có:

Thời gian đi từ A đến B là

x

40

(quãng đường chia vận tốc)

Thời gian đi từ B đến A là

x

30

Ta có phương trình:

x

40

+

x

30

=

3

,

5

x

=

60

(km)

Vậy quãng đường AB là 60km.

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