A) All triangles add up to 180° so when given two angles, add those up and subtract them from 180° . That will give you the missing angle.
3-5) When you do A above, and receive the measurement of angle 1, it will also equal 2 and you can repeat A for missing angle 3
6-8) Find the missing angle next to 1, and then subtract that from 180°. That number is the answer for 1. 2 is 55 as its a complimentary (i think thats the right term) angle. Which means it is on the opposite side of an angle. I don't remember how to find 3 however, its been a few years since I've done triangles.
