The question said that it told you the base angles. A roof would have two equal base angles. The base angles= 53
All the angles of a triangle each 180, (the roof is shaped like a triangle)
So, let's make x the missing angle.
53(2)+x=180
106+x=180
Subtract 106 on both sides.
180-106= 74
The vertex angle is 74.
I hope this helps!
~cupcake
