In the figure above, if \(AD\) is parallel to \(BC,\) then \(\angle ADC=\)
This topic has expert replies
-
- Legendary Member
- Posts: 2898
- Joined: Thu Sep 07, 2017 2:49 pm
- Thanked: 6 times
- Followed by:5 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
A. 11°
B. 22°
C. 33°
D. 46°
E. 134°
Answer: C
Source: Princeton Review
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
First, since angles in a triangle must add to 180°, we can see that the missing angle in the red triangle must be 180° - (x + 44)°
Simplify this measurement to get (136 - x)°
Finally, since AD is parallel to BC, we know that the two highlighted angles below must add to 180°.
So, we can write: (136 - x)° + 2x° + 3x° = 180°
Simplify: 136 + 4x = 180
Subtract 136 from both sides: : 4x = 44
Solve: x = 11
Our goal is to find the measurement of ∠ADC
Since ∠ADC = 3x°, we can replace x with 11 to get: ∠ADC = 3x° = 3(11)° = 33°
Answer: C