Question

OA and OB are opposite rays.

If $x={75}^o$, what is the value of y?

• A. ${105}^o$
• B. ${75}^o$
• C. ${45}^o$
• D. ${15}^o$

Answer 1

The correct option is A ${105}^o$

Sum of $x$ and $y$ is equal to ${180}^0$ (By Linear Pair)
A linear pair is a pair of adjacent, supplementary angles. Adjacent means next to each other and supplementary means that the sum of the measures of the two angles is equal to ${180}^o$.
$x={75}^0$
$=>x+y={180}^0$
$=>{75}^0+y={180}^0$
$=>y={180}^0-{75}^0={105}^0$