Question

Consider the figure:

If $\angle$A = ${50}^{\circ }$​, $\angle$B = ${70}^{\circ }$​. Then x+y is equal to (in degrees):

__

• A. ${60}^{\circ }$
• B. ${80}^{\circ }$
• C. ${100}^{\circ }$
• D. ${120}^{\circ }$

Answer 1

The correct option is D

${120}^{\circ }$

In triangle ABC

$\angle$A + $\angle$B + $\angle$C = 180${}^{\circ }$

$\angle$C = 180${}^{\circ }$ - (${50}^{\circ }$​ + ${70}^{\circ }$)

= 180${}^{\circ }$ - ${120}^{\circ }$ = 60${}^{\circ }$

We have

$x+y+\angle C={180}^{\circ }$

$x+y+{60}^{\circ }={180}^{\circ }$

$x+y={120}^{\circ }$