What is angle f to the nearest degree?

So we already knew all three sides, there are more than one way to do it, for example:

sin∠F = HG/HF = 12/13

cos∠F = GF/HF = 5/13

tan∠F = HG/GF = 12/5

ctg∠F = GF/HG = 5/12

All of them will give you the result which is approximately 67°.

a complex number is a number that can be expressed in the form a + bi, where a and b are real numbers, and i is a solution of the equation x2 = −1. because no real number satisfies this equation, i is called an imaginary number. has no real solution, since the square of a real number cannot be negative.

answer: -8.2562234e+13