Carcass wrote:
Attachment:
#GREpracticequestion In the figure, ABC is a right triangle..jpg
In the figure, ABC is a right triangle. What is the value of y ?
(A) 20
(B) 30
(C) 50
(D) 70
(E) 90
NOTE: The (poorly drawn) diagram tells us that ∠y = ∠ABCGiven: ABC is a
right triangle
This means that EITHER x = 90° and y = 70° OR y = 90° and x = 70°
This means we can already ELIMINATE answer choices A, B and C
Let's see what happens if x = 90° and y = 70°
Since angles on a line must add to 180°, we can see that that ∠BDC =
110°This causes a
big problem If we focus on triangle BDC (below)...
... we can see that two of the angles (90° and 110°) already add to 200°, which breaks the rule that says angles in a triangle always add to 180°
So it can't be the case that x = 90° and y = 70°
ELIMINATE answer choice D
By the process of elimination, the correct answer is E
Cheers,
Brent