You need to use trigonometry
1. Tan37=x/2.1
1.58=x
If it is a square, subtract (90+ whatever the other angle is) from 360. If it is a triangle than add 90 plus whatever other number the other angle is then subtract it from 180. A triangle is 180 degrees, and a square is 360 degrees.
SA= 108 m^2 aND the formula for surface area is SA=2bs+b^2
