Supplementary angles measure 180°. Make an equation:
[tex] x+(x+28) = 180 [/tex]
Subtract 28 to leave the variable in the parentheses alone:
[tex] x+(x+28-28) =180-28 \\ x+x = 152 [/tex]
Add the 2 x's together:
[tex] x+x = 2x [/tex]
Your new equation is:
[tex] 2x=152 [/tex]
Divide both sides by 2 to leave the variable alone
[tex] \frac{2x}{2} = \frac{152}{2} \\ \\ x = 76 [/tex]
The supplement measures 76°
