00:01
All right here, we're given this triangle, and it's triangle d -e -f.
00:04
So let me go ahead and draw it and label it.
00:07
And we see that triangle d -e -f is what's called an isosceles triangle, which means that this side and this side are the same length, right? when you use this little ticks to describe that.
00:21
Now, one of the theorems that we have is that if we have an isosceles triangle, then the base angles are congruent, which means that the two angles that are opposite the congruent sides are also congruent.
00:33
So what we have here is that this angle, angle d, is 25 degrees.
00:40
So that means that this is also 25 degrees, that angle f is also 25 degrees.
00:46
And so we are asked, what is the measure of angle e? so that's the one that we're looking for is the measure of angle e...