00:01
Okay, a cylinder has a circular base area of 30 centimeters squared and a height of 5 centimeters.
00:06
What is the radius of the circular base area? so to find the area of that base, what you have to do is the formula is pi times the radius squared.
00:16
So if area equals 30 centimeters squared, then that's pi times the radius squared.
00:24
So i'm going to divide by pi.
00:27
So 30 divided by pi.
00:33
And i'm getting 9 .5 equals the radius squared.
00:41
And then i have to find the square root of 9 .5.
00:56
And it is approximately 3 .1 is the radius.
01:01
And it says, so the radius is 3 .1 centimeters.
01:08
What is the total surface area of the cylinder? so to find surface area of a cylinder, you're going to do two times pi times the radius squared plus two times pie times the radius times the height.
01:21
So the surface area would equal two times 30 plus two times pi times the radius of 3 .1 times the height of 5.
01:32
So surface area equals 60 plus 2 times 3 .14 i'm using for pie.
01:43
Times 3 .1 times 5 and that is 97 .34.
01:52
So surface area equals 97 .34 plus 60 is 157 .34 and that's centimeters squared.
02:03
So surface area of a cylinder is 157 .34 centimeters squared...