1. EXAMPLE 2 Use properties of parallelograms So, m ADC + m BCD = 180°. Because m ADC = 110°, m BCD =180° –110° = 70°. SOLUTION By Theorem 8.5, the consecutive angle pairs in ABCD are supplementary. Desk Lamp As shown, part of the extending arm of a desk lamp is a parallelogram. The angles of the parallelogram change as the lamp is raised and lowered. Find m BCD when m ADC = 110°.

2. EXAMPLE 3 Standardized Test Practice SOLUTION By Theorem 8.6, the diagonals of a parallelogram bisect each other. So, P is the midpoint of diagonals LN and OM. Use the Midpoint Formula. The correct answer is A. ANSWER = Coordinates of midpoint P of OM 4 + 0 2 7 + 0 2, ( ) = 7 2, 2 ( )

3. GUIDED PRACTICE for Examples 2 and 3 NM 3. Find the indicated measure in JKLM. ANSWER 2 KM 4. ANSWER 4 m JML 5. ANSWER 70° m KML 6. ANSWER 40°