00:01
Today we're going to be finding the surface area of this cone.
00:05
Now we have our side length, our slant height here, which is 17 .3 centimeters, and we know that the diameter is 10 .4 centimeters.
00:13
We can use this formula to find the surface area of a right cone.
00:18
This area formula says pi times the radius squared plus pi times radius times the slant height.
00:26
This first formula here is the area of the base of the circle.
00:30
This second part of the formula here is the lateral area of the cone.
00:36
So to do this, we can plug in the variables that we do know.
00:41
We know that our slant height or our value of l is equal to 17 .3, and we know that the diameter of the base of the cone is equal to 10 .4.
00:56
Now, in this formula, it's not asking us for diameter.
00:59
It's asking us for radius.
01:00
So to find our radius, we're going to take the value, of our diameter, 10 .4, and divided by 2.
01:06
This is equal to 5 .2.
01:09
So now we have everything that we need to solve this formula.
01:14
Also, within this formula, we're going to say that pi is equal to 3 .14.
01:20
So now we can solve this equation...