Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
In the triangles above, 3 times (y minus x) =
(A) 15
(B) 30
(C) 45
(D) 60
(E) 105
The correct answer is C
Explanation
To evaluate the expression 3 times (y minus x), it is necessary to determine the values of x and y. Since the sum of the measures of the angles of any triangle is 180 degrees, and a right angle has measure 90 degrees, the value of x can be found by solving the equation x + x + 90 = 180. This yields x=45. The value of y can be found by solving the equation y + y + y = 180. This yields y=60. Finally, the values for x and y are substituted into the expression 3 times (y minus x) to obtain 3 times (60 minus 45) = 3 times (15) = 45.