00:01
So what is an isosceles tripezoid? well, recall that isosceles means two sides are equal.
00:07
Trapezoid has one pair of parallel sides.
00:11
And then i have two sides that are equal.
00:12
They can't be my base.
00:14
But i know the perimeter, if i were to add all these sides up, is 40.
00:18
Okay.
00:19
So my bases are 11 feet and 19 feet.
00:23
And i'm not sure what my sides are, but i know if i add all these up, my perimeter distance around the outside, it'll be equal to 40.
00:32
Okay, so what's 11 plus 19? well, this is going to be 2 x plus 30 equals 40.
00:39
Just solving this, so opposite operation, you get things to the other side, subtract 30 from both sides, multiplying by 2, opposite i'm multiplying by 2.
00:48
I'm going to divide by 2.
00:50
So this gives me my sides are 5.
00:53
But did i solve this problem? no, i need to find the area of a trapezoid.
00:58
What's the area of a trapezoid? well, it's the average of the basis times the height.
01:06
But the height has to be perpendicular to the basis.
01:09
Okay, so how can i figure this out? well, since this is the nice sleys trappazzo, i know that these two sides are going to be equal...