Question

Consider the figure:

If $\angle$A = ${50}^{\circ }$​, $\angle$B = ${70}^{\circ }$​, and x = 2y, then, find the value of x (in degrees)

• A. 80°
• B. 40°
• C. 85°
• D. 40°

Answer 1

The correct option is A

80°

x + y = $\angle A+\angle B$ (exterior angle property)
= ${50}^{\circ }$​ + ${70}^{\circ }$​

= ${120}^{\circ }$​
3y = ${120}^{\circ }$​ (since x = 2y)
y = ${40}^{\circ }$​
x = 2 x 40 = ${80}^{\circ }$​,