Since this is a right triangle we can use trig functions
First we can find the length of the hypotenuse using the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
28^2 + 45^2 = c^2
784+2025 = c^2
2809 = c^2
Taking the square root of each side
sqrt(2809) = sqrt(c^2)
53 = c
The hypotenuse, DR = 53
Then we can find the measurements of the angles
sin F = opp/ hyp
sin F = 28/53
Taking the inverse sin of each side
sin D = opp/ hyp
sin D = 45/53
Taking the inverse sin of each side