so to answer this, you need to use pythagoras' theorem (a² + b² = c²). So its kinda like a triangle with the hypotenuse being the angled part of the pole that fell.
if c is the hypotenuse then you must sub into the formula
36² + 27² = c²
1296 + 729 = c²
2025 = c²
so to find c, you must find the square root of 2025
√2025 = 45
however the question is asking what the full length of the pole was before it broke so that would be the part that fell (45ft) + the part remaining (36ft), so the answer is 81ft