00:03
Okay, so for this problem, i'm going to refer to theorem two from section 6 .5 and theorem four, also from 6 .5.
00:31
Well, both of these pretty much say that, so theorem 2 says that if the diagonals of a parallelogram are congruent, then the parallelogram is a rectangle.
00:43
So we're going to start with that.
00:47
So let me draw this figure.
00:58
Okay, so we want the diagonals of the parallelogram to be congruent.
01:04
So first let's label this as a, b, a, b, c, and d.
01:21
And now let's draw the diagonals, d, b, and a, c.
01:35
Okay, so using the first theorem, theorem two.
01:41
So theorem two says that the diagnos are going to be congruent...