The ratio of the angle measures in a quadrilateral is 1 : 4 : 5 : 6. Find the measure of the largest angle.

A. 135°
B. 145°
C. 90°
D. 112.5°

Question

The ratio of the angle measures in a quadrilateral is 1 : 4 : 5 : 6. Find the measure of the largest angle.

A. 135°
B. 145°
C. 90°
D. 112.5°

anonymous · Answer

let x be the ratio

1x + 4x + 5x + 6x = 360 (because the quadrilateral's interior angles sums up to 360)

16x = 360  divide both sides by 16 to get x

x = 22.5  

Substituting it to the biggest number in the ratio, we have

6x = 6(22.5) = 135

therefore, the answer is A.

anonymous · Answer

1x+ 4x+ 5x+ 6x=360
                      16x=360
                          x=360/16
                          x=22.5
6*22.5=135
is :  A. 135°