Look at the figure, O PORS. Find the mZP,
12
36°
140"
144"

m∠P = 144°
Solution:
PQRS is a parallelogram.
m∠P = 12a°, m∠Q = (4a - 12)° and m∠S = 3a°
In parallelogram, opposite angles are congruent.
m∠Q = m∠S
4a° - 12° = 3a°
Add 12° on both sides.
4a° - 12° + 12° = 3a° + 12°
4a° = 3a° + 12°
Subtract 3a° on both sides.
4a° - 3a° = 3a° + 12° - 3a°
a° = 12°
To find the measure of angle P:
m∠P = 12a°
= 12(12°)
m∠P = 144°