Answer: Choice E
15, 75, 90; right
===================================================
Step-by-step explanation:
The ratio 1:5:6 scales up to x:5x:6x for some positive real number x.
The three interior angles are x, 5x and 6x. For any triangle, the interior angles always add to 180.
x+5x+6x = 180
12x = 180
x = 180/12
x = 15
So,
- 5x = 5*15 = 75
- 6x = 6*15 = 90
The triangle has angles of 15, 75 and 90 degrees.
Because we have a 90 degree angle, this is a right triangle.
Note how 15+75+90 = 180 to help confirm the answer.