00:01
Okay, i put our formulas here because that's just the easiest way to do it.
00:09
And i'm going to, let's do the cylinder first, because the cylinder is by far the easier of the two.
00:20
I'll tell you what all the surface area for the pyramid means in a minute.
00:24
But r is our radius, so two times pi times the radius, so eight squared plus two times pie, times the radius is 8 times the height is 12.
00:38
So that 64 times 2 is 128 pi plus 8 times 12 is 96 times 2 is 192 pi.
01:07
So 128 plus 192 is 320 pi square feet.
01:17
Or those are inches, sorry, square inches.
01:25
How many decimal places it say to the nearest tenth so we need to do 320 times pi so that's the surface area equals 1 ,05 .3 square inches so that's for your cylinder now back to the pyramid so l is the slant height and p is the point perimeter of the base and big b is the area of the base okay so we can find the area easy we can find the perimeter easy of the base but what's kind of difficult is the slant height the slant height is this here now i'm going to come across that's the center so this is if this is 14 halfway across is seven this is 12 and that's going to be a right angle so i've got to find, i've got to use a squared plus b squared equals c squared to find the side of that triangle, which is going to give me my slant height...