Question

If 4 congruent circles are inscribed in a square with a side length of 20mm as shown, find the area of the shaded region
http://tinypic.com/r/wbxoit/7


Please explain how to do this

Answer 1

Do you know how to find the area of a circle?

Answer 2

I dont remember the formula

Answer 3

400mm^2 - (4 * \[5^{2}*\])

Answer 4

25pi

Answer 5

Area = \(\pi \cdot r^2 \)
Can you give me the radius of 1 circle?

Answer 6

I dont have the radius

Answer 7

5, the length of the whole side is 20, and if two circle span the length of the square then each circle has a length of 10mm, so the radius is 5mm

Answer 8

So 3.14*R^2 and thats my anwser?

Answer 9

mulitply that my 4 since there are 4 circles, and you need to find the area of the gray part so you need to subtract the area of the circle from the area of the square

Answer 10

I got a huge number. That isnt right. So you do 3.14*R^4 then subtract the area?

Answer 11

no....
find the area of 1 circle, then multiply that by 4 since you have 4 circles.
take that answer and subtract it from the area of the square and that will give you the area of the shaded region.

Answer 12

Oh ok! hold on. let me do that.

Answer 13

321.5?

Answer 14

area of the square = 20*20 = 400
area of 1 circle = 25pi, so area of all 4 circles is = 100pi
so area of shaded region = 400 - 100pi = 400 - 314 = 86

Answer 15

Okay. I understand what I was doing wrong. I was getting 400 but messing up after that. Thanks guys

Answer 16

yw