Question

does anyone have an idea on how to solve this? check out the attachment in the comment box for the question

Answer 1

let's start off by finding the area of the whole circle

Answer 2

what is the area of the whole circle?

Answer 3

360?

Answer 4

that's the number of degrees of rotation it takes to turn in a full circle

but that's NOT the area of the circle

Answer 5

you use this formula

A = pi*r^2

A = area
pi = 3.14 (approximately)
r = radius

Answer 6

3.14 * 155^2 = 75438.5

Answer 7

the radius is NOT 155

Answer 8

try again

Answer 9

the radius is the distance from the center of the circle to the outer edge of the circle

Answer 10

okay so 4.3^2?

Answer 11

don't forget pi

Answer 12

4.3^2 * 3.14 = 58.05?

Answer 13

I'm getting 58.0586, but yes roughly

Answer 14

So the area is approximately 58.0586

This is the area of the entire circle. If the arc was 360 degrees, we'd be done because 360 degrees makes a full circle.

But the arc is NOT 360 degrees

Answer 15

so you have to multiply this area by (155/360)

notice how the arc angle 155 is over the full revolution of 360 degrees

Answer 16

notice how if the arc was 180 degrees, then 180/360 reduces to 1/2

so if the arc was 180 degrees (it's not, but let's say it is), then you multiply the full area by 1/2...ie cut the area in half

Answer 17

ooooh! okay so 58.0586(155/360) = 24.997

Answer 18

I'm getting 24.9974527777778, so yes

Answer 19

that rounds to 25 square inches

Answer 20

thank you so much!

Answer 21

you're welcome

Answer 22

sorry to bother you again @jim_thompson5910 I did the same steps as the previous problem..& my answer isn't apart of the answer choices.
5.4^2 * 3.14 = 91.5624(180/360) = 45.7812

Answer 23

5.4 is the diameter, NOT the radius

Answer 24

remember: radius is the distance from center to edge

Answer 25

I wasn't aware of that, sorry. Can you help me through this?

Answer 26

that's ok and sure

Answer 27

diameter = 5.4

radius = take half of diameter = 5.4/2 = 2.7

so r = 2.7

Answer 28

try it again

Answer 29

11.4453?

Answer 30

you're doing 2.7^2*3.14 right?

Answer 31

oh wait, you cut that in half

so yes, that's the correct answer

Answer 32

so 11.45 is the closest thing there (we have round off error because of the approximate value of pi)