First, replace all variables with the given values.
12(9) + 9(2) + 2(12)
This should then equal 150, then the formula says to multiply this answer by 2. Doing so, should give a final answer of 300.
The first one since the given measurements/guide is Side, Angle, Side
It looks like the first and the third are diagrams of similar triangles, and the third needs another right angle marker at E to be persuasive. So I'll go with
First diagram
We're given a congruent angle pair and we have another from vertical angles, so AA, similar triangles.
