Maths problem, i don't know how to do and write the reason, because i don't know how to prove EC is perpendicular to BF, thanks?

Question

Answer 1

最愛解答

side BC = side FC and side BE = size EF, thus triangle BCE and FCE triangle are similar per SSS similarity theorem.

So, the angle BEC and the angle FEC are the same, thus 90 degrees.

So proved.