## Elementary Technical Mathematics

$$\angle 1= \angle 2=45^o.$$
Since $\angle 1, \angle 2$ are complementary, then $\angle 1+ \angle 2=90$. Assuming that $\angle 1= \angle 2$, then $$2\angle 1=90$$ that is $$\angle 1= \angle 2=45^o.$$