Question

a section of a roller coaster track forms a parallelogram abcd. if m∠abc = 72°, what is m∠dab? a 72° b 108° c 144° d 216°

Explanation:

Step1: Recall property of parallelogram

Adjacent angles of a parallelogram are supplementary.

Step2: Set up the equation

Let $\angle ABC = 72^{\circ}$ and $\angle DAB$ be adjacent to $\angle ABC$. So $\angle ABC+\angle DAB = 180^{\circ}$.

Step3: Solve for $\angle DAB$

$\angle DAB=180^{\circ}-\angle ABC = 180 - 72=108^{\circ}$.

Answer:

B. $108^{\circ}$