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