square based triangle

Question

Consider a square-based straight pyramid. Suppose that the base is a square with sides 1616 in long, and all other edges are 1414 in long. Find an approximate value of the angle formed between the base and a triangular face. Present your answer in degrees, accurate up to four or more decimal places.

Answer 1

the hypotenuse of triangle with angle to be found, call TH

TH=√(14²-(16/2)²)

The angle will have property, 16/2=TH*cos(angle)

angle=cos^-1(8/TH)

If you use 14 as TH you will have wrong answer. Need to calculate TH first.

Answer 2

This is basic Pythagoren Theorem. Use it!