Answer:
52
Step-by-step explanation:
Two triangles are similar
m<B = m<E
m<C = m<D
m<A = m<F
now, the sum of interior angles in a triangle is equal to 180
angle B is given as 40 (so angle E is also 40) and angle D is given as 88 to find m<F:
40 + 88 + m<F = 180 add like terms
128 + m<F = 180 subtract 128 from both sides
m<F = 52
