In parallelogram PQRS, ∠P=(2x)° and ∠Q=(3x)°. Find ∠P (in degrees).
Class 9QuadrilateralsGeometry — Quadrilaterals
A79
B72
C65
D144
Step-by-Step Solution
∠P and ∠Q are adjacent (supplementary): 2x+3x=180 → 5x=180 → x=36. ∠P=2x=72°.
Answer: B) 72
Key idea: Special parallelograms
**Rectangle** (parallelogram + all angles 90°): - All properties of a parallelogram. - Diagonals are EQUAL (in addition to bisecting each other).
**Rhombus** (parallelogram + all sides equal): - All properties of a parallelogram. - Diagonals bisect each other AT RIGHT ANGLES. - Diagonals also bisect the angles of the rhombus.
**Square** (rectangle + rhombus): - All properties of both. - Diagonals: equal, bisect at right angles, AND bisect angles.
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