Question

A. 90 degrees

B. 45 degrees

C. 30 degrees

D. 120 degrees

Answer 1

For this case we have by definition, that each of the four internal angles of a square measure 90 degrees.

If we draw the diagonals of the square then the angles are divided by two, that is:

$\frac {90} {2} = 45$

Thus, angle 3 measures 45 degrees.

$A3 = 45$

By definition, the sum of the internal angles of a triangle is 180 degrees.

So:

$A2 + A3 + 90 = 180\\A2 = 180-90-A3\\A2 = 180-90-45\\A2 = 45$

Thus, angle 2 measures 45 degrees.

Answer:

45 degrees