May do this in stages, depending on how Sam goes in front of the TV.

Question 1 - I assume you know an angle in that triangle somewhere? I'd assume you're being asked to find the side with the ?m label, but you'd need an angle apart from the right angle somewhere.

Question 2 - Perpendicular height of a triangle... Is it an equilateral (all sides equal) triangle or an isosceles (two sides equal) triangle? The explanation for how to do those two varies from the explanation for a scalene (no sides equal) triangle and I don't want to confuse you with excess info that you don't need!

BW