Answer:
46.7 degrees.
Explanation:
According to the given information, triangle DEF is a right triangle with angle F as the right angle. We are trying to find the measure of angle D.
We are given the opposite side length (6.4 feet) and the hypotenuse (8.8 feet), so we can use sine to calculate the angle measure (SOH = Sine; Opposite over Hypotenuse).
sin(D) = 6.4 / 8.8
sin(D) = 64 / 88
sin(D) = 8 / 11
D = arcsin(8 / 11)
D = arcsin(0.72727272727272727272727273)
D = 46.65824177.
So, the measure of angle D is about 46.7 degrees.
Hope this helps!