angles Y and Z are supplementary angles. If measure angle Y is two-thirds measure angle Z, what is measure angle Y?

Answer 1

2 unknowns, therefore 2 equations are required. The first one comes from the definition of "supplementary angles":

Y + Z = 180

For the other equation:

"measure angle Y is two-thirds measure angle Z"-------so:

Y = 2/3 * Z

Use this to substitute for Y in the 1st equation:

2Z/3 + Z = 180

So:

5Z/3 = 180

multiply both sides by 3/5:

Z = 180*3/5 = 108

From either equation, we can then get Y = 72