Answer:
Strictly speaking, there is not enough information to solve the problem.
If we assume m<EFY = 90, then:
m<DEY = 29
m<DEF = 58
Step-by-step explanation:
Going by the exact information shown, the answer is really that there isn't enough information to answer the question.
On the other hand, if angle EFY is a right angle, then we have two right triangles that can be proved congruent by HL. Then by CPCTC, angles DEY and FEY are congruent. We set their measures equal and solve for y.
4y - 7 = 2y + 11
2y = 18
y = 9
m<DEY = 4y - 7 = 4(9) - 7 = 36 - 7 = 29
m<DEF = 2m<DEY = 2(29) = 58
