Answer:
A = 45°
Step-by-step explanation:
All angles in a triangle add up to 180°.
We know that one angle in the triangle is 90° (this is known because of the small square).
Hence:
A + A + 90° = 180°
Simplify
2A + 90° = 180°
Rearrange
2A = 180 - 90
2A = 90
Divide both sides by 2, so that A is by itself
A = 45°
