Area and Circumference of a Circle

Question

alina123 · Answer

attachment

beccaboo333 · Answer

Yeah sorry I'm not sure. I haven't done these kinds of problems in a long time. @iPwnBunnies

ipwnbunnies · Answer

Look at Question 1. They give us the diameter in inches, but we want it in feet. We want it in feet because the given cost is $3.50 per square feet.

alina123 · Answer

oh

ipwnbunnies · Answer

square foot* :3
The diameter is 36 inches. Do you know how many feet that is?

alina123 · Answer

3

ipwnbunnies · Answer

Good. The diameter is 3 feet long. What's the length of the radius?

alina123 · Answer

1.5 ft

ipwnbunnies · Answer

Good. Can you find the area of the circle?

alina123 · Answer

7.065 in squared

alina123 · Answer

i mean ft

ipwnbunnies · Answer

Good, 7.065 square feet. So, the cost per square foot to paint it is $3.50. How much will it cost to paint the sign?

alina123 · Answer

25 dollars

ipwnbunnies · Answer

There ya go. :D

alina123 · Answer

k the next one is it a

ipwnbunnies · Answer

Yes. :)  The entire curve is like the circumference of one circle. Since they gave you the diameter, C = pi*diameter. So yes, it's A. XP  Just wanted to explain it a bit lol.

alina123 · Answer

k and i just need help with the last 2

ipwnbunnies · Answer

Alright, this one is a bit complicated. Can you see that the shaded region would be the area of the square MINUS the area of all the circles?

alina123 · Answer

yes

ipwnbunnies · Answer

Good. Find the area of one circle, multiply it by 9, b/c there are 9 circles.
The length of one side of the square will be the diameter of 3 circles, right?
Can you take it from here? :3

alina123 · Answer

so so far the area of the circles are 706.5 cm

ipwnbunnies · Answer

Ok.

alina123 · Answer

30 cm is one side length of the square

ipwnbunnies · Answer

Right.

alina123 · Answer

what do we do with the squares areas now

ipwnbunnies · Answer

You have the square's area? 900 cm^2?
As I said, we're trying to find the shaded region. That would be the area of the square MINUS the area of all the circles. Simple subtraction now :)

alina123 · Answer

so 193.5

alina123 · Answer

is number 4 asking for circumference

ipwnbunnies · Answer

Sorta. It's asking how far will it go in 10 rotations.
Look at it like this way: 1 rotation will equal to the circumference.

alina123 · Answer

ok so i could multiply it by 10

ipwnbunnies · Answer

Yes, you can multiply the Circumference by 10. :)

alina123 · Answer

ok so thanks so much! :)

ipwnbunnies · Answer

No prob. :)