SOLUTION: ∠DEF and ∠ABC are supplementary angles and ∠DEF is four times as large as ∠ABC. Determine the measure of each angle, show all your work

You can put this solution on YOUR website!
∠DEF and ∠ABC are supplementary, meaning they add up to 180°

x = ∠ABC
4x = ∠DEF {∠DEF is four times as large as ∠ABC}

x + 4x = 180 {supplementary angles add up to 180°}
5x = 180 {combined like terms}
x = 36 {divided both sides by 5}
4x = 144 {substituted 36, in for x, into 4x}

∠ABC = 36° and ∠DEF = 144°
www.algebrahouse.com