00:01
Okay, so here we have to find the volume of a combination of three shapes.
00:06
Now, to do that, we have to know the formula for each one.
00:10
So here the cone, the formula is one -third pi times the radius squared times a height.
00:15
Sphere is going to be four -thirds pi, r to the third power, and cylinder is going to be pi r squared times a height.
00:23
Okay.
00:23
Now, the key here, though, is what is a radius and what is the height of this? now, they give us a height of all three shapes.
00:31
We don't know the radius of the sphere, the cone, or the cylinder.
00:35
But we do notice that they give us half a circle.
00:38
And the height of half a circle is five meters.
00:42
So since the height of half a circle is five meters, it's the same as saying the radius of the circle.
00:47
Okay, so for the first one, it would be one -third times pi times five squared times h, which your height of the cone is going to be 15.
01:02
For the second one, it's going to be now, the sphere, since it's half a sphere, whatever value you get, you're going to divide it by two.
01:10
Okay.
01:11
So for this case, it's going to be, let me put a little more space here.
01:16
Okay, so for this one, it's going to be four thirds pi times five to the third power.
01:24
All this is going to be divided by two.
01:26
Okay, so whatever you get in your answer here, you're going to divide that answer by two, and that's going to be your real answer, okay, because it's only half a circle...