Question

Study the markings on each figure and decide whether ABCD must be a parallelogram. If the answer is yes, state the definition or theorem that applies.

Short answer

No, the given figure ABCD is not a parallelogram.

Step-by-step solution

Step 1. Observe the given diagram.

The given diagram is:

Step 2. Description of step.

From the given diagram it can be noticed that:

$\angle ABC=\angle ADC=70°$.

Therefore, $\angle ABC\cong \angle ADC$.

That implies the one pair of opposite angles of the quadrilateral are equal.

No information is given about the other pair of opposite angles.

Therefore, the given quadrilateral ABCD is not a parallelogram.

Step 3. Write the conclusion.

No, the given figure ABCD is not a parallelogram.