00:01
Given this figure, if ad equals 4, ab equals 3, and cd equals 9, find the area of triangle a, e, c.
00:12
So, ab equals 3, i'm going to go ahead and put that on there, cd equals 9.
00:17
I'm trying to find the area of triangle a, c, e, so this triangle shape that's in green.
00:30
And there are a couple things that i can do for this.
00:36
One of the things that i can do is i can use what i know about similar triangles.
00:42
I'll also be using what i know about pythagrin theorem.
00:48
The first thing that i know is that triangle c -d -e is similar to triangle b -a -e, in part because we have vertical angles here.
01:01
So with vertical angles, we have all three angles similar to each other, which means the sides will be similar with a scale factor.
01:11
Side a, b is similar to side c, d.
01:15
So that tells us that our scale factor here is...
01:24
Now, i was told at the beginning, that a, d, the full length of that side, is four...