Question

A mountain climber is at an altitude of 2.9 mi above the earths surface. From the climbers viewpoint what is the distance to the horizon

Answer 1

we know that
applying the Pythagorean theorem
(3959+2.9)²=x²+3959²
x²=(3959+2.9)²-3959²
x²=3961.9²-3959²
x²=22970.61
x=√22970.61
x=151.56 mi

the answer is
x=151.56 mi