Can you solve the Hanging Cable problem?

[dlevere]

A cable of 80 meters is hanging from the top of two poles that are both 50 meters off the ground. What is the distance between the two poles (to one decimal point) if the center cable is (a) 20 meters off the ground and (b) 10 meters off the ground?

Presh Talwalker of Mind Your Decisions says the above riddle was used as an Amazon interview question. His video has the answer.

Source

[bungholio]

I've seen that one on reddit before in reference to an Amazon interview question. The answer was not technically 0 because that's not possible, but really close. It's something visually incorrect.