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°

$12. that is my answer.