An exterior angle is equivalent to the two most isolated (as in the ones all the way on the other side) interior angles combined.
So this means that m∠Y is equivalent to 138° - 79° which is 59°
Now that we know m∠Y we can find m∠XZY.
Well as I had mentioned earlier a triangle has 180° we can add the two interior angles that we know and subtract it by 180°.
m∠Y and m∠X together is 59° and 79° respectively which is 138°. Now let's subtract it by 180° and get 42°
m∠XZY = 42°
m∠Y = 59°
I hope that helps you out!!
Any more questions, please feel free to ask me and I will gladly help you out!!
using fethagorth equation
An isosceles triangle has 2 sides that are the same length. Let's say that our triangle has the 2 sides measuring the same and the base is a different length. The vertex angle is the top angle. By the definition of an isosceles triangle, since the 2 sides measure the same length, then the angles across from those sides have the same degree measure. If we know the measure of the vertex angle, then we have
180 = vertex angle - base angle - base angle
but since the base angles are the same and we have 2 of them, then
180 = vertex angle - 2 base angles
For example, if the vertex angle measures 80 degrees, then 180 - 80 = 100. That 100 has to be split in half for each of the base angles which are the same as each other. So the vertex angle is 80 and each base is 50.
i hope this , i don't know if you're looking for a pair or not.