a)
Since it is an isosceles triangle, it has 2 equal angles (base angles) .
all the interior angles of a triangle add up to 180°.
So:
m< F+ m
and:
m
Since both are equal we can say that both angles are 2x
2x + 30 = 180
Solve for x
2x = 180 -30
2x = 150
x = 150/2
x = 75°
m