GMAT Official Guide 2019 In the figure shown

BTGmoderatorDC wrote:

In the figure shown, what is the value of x ?


A. 60

B. 80

C. 85

D. 90

E. 95

Since angles on a line must add to 180°, we can see that there are three 30° angles in our diagram...


Next, let's focus on the BLUE triangle.

Since angles in a triangle must add to 180° (and since we already have two angles measuring 30° each), the third angle must be 120°

Next, we have two angles sharing the same GREEN line.

Since angles on a line must add to 180°, we can see that the other angle must be 60°

Finally, we can focus on the RED triangle.

Since angles in a triangle must add to 180° (and since we already have two angles measuring 30° and 60°), the third angle (x) must be 90°

Answer: D

Cheers,
Brent