Find measure of angle if it is 20 more than 4 times its supplement

Hello!

Supplementary angles add up to 180. This gives us the system of equations below.

a+b=180

b= 4a+20

Now we plug our b value into the first equation and solve for a.

a+4a+20=180

We combine like terms.

5a+20=180

We subtract 20 from both sides.

5a=160

We divide both sides by 5.

a=32

Now we want to find our angle b. We can plug our a value into the equation.

b=4(32)+20

128+20=148

Therefore, our angle measure is 148°.

I hope this helps!

irrational, cannot