Question

Find the complementary angle of ${20}^{\circ }+y^{\circ }$

Answer 1

We know that two angle are said to be complementary if their sum is ${90}^{\circ }$
Let the complementary angle of ${20}^{\circ }+y^{\circ }$ be $x$.
$\therefore ({20}^{\circ }+y^{\circ })+x={90}^{\circ }$
$x={90}^{\circ }-({20}^{\circ }+y^{\circ })$
$x={90}^{\circ }-{20}^{\circ }-y^{\circ }$
$\therefore x=(70-y{)}^{\circ }$
Hence complement angle of $({20}^{\circ }+y^{\circ })$ =$(70-y{)}^{\circ }$