Word problem involving distance and Pythagorean’s theory

Question

Can you see Niagara Falls (F) from Toronto (T) if a person (P) is standing H kms above Toronto. The distance from Toronto to Niagara Falls is 67km. The Earth’s radius is 6366kms

Answer 1

as long as the angle is less than pi/2. Otherwise you will be directly above the Falls.

tan x = H/67 where H is Height

Then x = arctan ( H/67)

H/67 < pi/2

h < 105 1/4 meters