Question

A 20° sector in a circle has an area of 21.5π yd².

What is the area of the circle?

Use 3.14 for pi.

Enter your answer as a decimal in the box.

Answer 1

@Hanna

Answer 2

@bill533 how many degrees are there in a circle?

Answer 3

360

Answer 4

And what is 360/20 ?

Answer 5

18

Answer 6

Okay multiply that by 21.5pi

Answer 7

To get the area of the circle

Answer 8

is it 1215.18 or do i leave the 18 out since it asked for a decimal?

Answer 9

The 18 IS a decimal

Answer 10

oh ok

Answer 11

What is the area of a sector with a central angle of 2π/9 radians and a radius of 16.7 ft?

Use 3.14 for π and round your final answer to the nearest hundredth.

Enter your answer as a decimal in the box.

Answer 12

is it 97.35 square feet or 97.30 ?

Answer 13

The formula for this is \(S = r\theta\)

Answer 14

correct

but 2*PI / 9 radians = 40 degrees

Answer 15

Yes, correct, but I don't think you're supposed to convert to degrees. You're supposed to use 3.14 for pi

Answer 16

oh ok

Answer 17

but due to my calculations it appears the result is 30.99π ft²

Answer 18

Explain how you got that

Answer 19

Easy

Substituting

and multiplying the area

Answer 20

I think I gave you the formula for something else. Sorry

Answer 21

Well simply, it's like this

((2π/9)/2π) x 278.89π ft² = 30.99π ft²

Answer 22

When in doubt, just use this formula for these kinds of problems:
\(\dfrac{a}{360} = \dfrac{b}{\pi r^2} = \dfrac{c}{2 \pi r}\)

a represents the measure of the sector
b represents the area of the sector
c represents the measure of the arc of the sector.

Answer 23

That's what i did to calculate the area of the sector

Answer 24

Koolio