Question

In the diagram, what is the value of x?

A. 144°
B. 28°
C. 5°
D. 36°

Answer 1

x+4x=180 (A and B are parallel)
4x5=20 and the angle doesn’t equal to 20(it’s abtuse)so it’s not 5
And 4x144=576 impossible
We still have 2 possibilities 36 and 28
If x=28 then x+4x=180 but x+4x=140<180
It’s also impossible so the correct answer is D.36(36+4x36=180)

Answer 2

Remark

You can show that x and 4x are supplementary. The angle added to x on the same side of traversal is equal to 4x.

x + 4x therefore = 180 degrees. Add the like terms on the left.

5x = 180 degrees. Divide by 5

5x/5 = 180/5

x = 36

Answer x is 36 degrees. D.