00:02
So for a, i'm going to do pi times the radius squared of the bigger circle, and then i'm going to subtract two times pi times the radius squared of the two smaller circles.
00:11
So the larger circle is 8 centimeters, so 3 .14 times 8 squared minus 2 times pi times the radius of 4 squared.
00:25
So 3 .14 times 64 minus 2 times pi times 16.
00:35
So 3 .14 times 64 is 200 .96 minus 2 times 16 times 3 .14.
00:53
And that's 100 .48.
01:02
200 .96 minus 100 .48 is 100 .48.
01:12
And that's in centimeters squared.
01:15
Okay.
01:16
B, i'm going to do just 8 times 2 divided by 2 plus pi times radius squared divided by 2.
01:29
So 8 times 2 is 16.
01:31
16 divided by 2 is 8 plus 3 .15.
01:36
Times 4 squared divided by 2.
01:43
So 8 plus 3 .14 times 16 divided by 2.
01:49
So 3 .14 times 16 divided by 2 is 25 .12.
01:56
So 8 plus 25 .12.
02:01
So that's 33 .12 and that's in centimeters squared.
02:07
Then for the next one, this shape is going to fill in this shape.
02:15
So i'm just going to do pi times the radius squared divided by 2...