Study Material — 1 PYQs (2018–2018) · Concept Notes · Shortcuts
SSC CHSL Quadrilaterals is a frequently tested subtopic — 1 previous year questions from 2018–2018 papers are included below with concept notes, key rules and shortcut tricks.
finding area when diagonals are given, calculating perimeter from given conditions, property-based questions, and coordinate geometry problems involving quadrilaterals
⚡Powerful Shortcut - Diagonal Rule
For any quadrilateral with perpendicular diagonals, Area = (1/2) × d1 × d2. This works for rhombus, kite, and square. This single formula can solve multiple question types quickly.
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Worked Example
Solve this step-by-step before moving on
1
Step 1
Find Area
Area = (1/2) × d1 × d2
Area = (1/2) × 16 × 12 = 96 cm²
2
Step 2
Find Side Length
Diagonals of rhombus bisect at right angles.
Half diagonals: 8 cm and 6 cm
Using Pythagoras: Side = √(8² + 6²) = √(64 + 36) = √100 = 10 cm
3
Step 3
Find Perimeter
Perimeter = 4 × side = 4 × 10 = 40 cm
Another Time-Saving Trick:
When a quadrilateral's vertices are given in coordinate geometry, use the shoelace formula: Area = (1/2)|x1(y2-y4) + x2(y3-y1) + x3(y4-y2) + x4(y1-y3)|. This eliminates the need for multiple calculations.
Common Mistake:
Students often confuse rhombus and square properties. Remember: Square has all properties of rhombus PLUS all angles are 90°. Rhombus doesn't necessarily have 90° angles. Also, many forget that in trapezium area formula, height is the perpendicular distance between parallel sides, not the slant side length.
Key Points to Remember
Sum of interior angles in any quadrilateral = 360°
Parallelogram: Opposite sides parallel and equal, diagonals bisect each other
Rectangle: All angles 90°, diagonals equal and bisect each other
Square: All sides equal, all angles 90°, diagonals equal and perpendicular
Rhombus: All sides equal, diagonals perpendicular and bisect each other
For perpendicular diagonals: Area = (1/2) × d1 × d2
Trapezium area = (1/2) × (sum of parallel sides) × height
Kite has two pairs of adjacent sides equal, one diagonal bisects other perpendicularly
Exam-Specific Tips
Sum of all interior angles in any quadrilateral is exactly 360°
Rhombus area formula: (1/2) × d1 × d2 where d1, d2 are diagonals
Square is the only quadrilateral that is both rectangle and rhombus
In parallelogram, opposite angles are equal and adjacent angles are supplementary
Trapezium has exactly one pair of parallel sides
Rectangle diagonals are always equal in length
Kite has exactly two pairs of adjacent sides equal
In any parallelogram, diagonals bisect each other but are not necessarily equal
Practice MCQs
Quadrilaterals — Practice Questions
17graded MCQs · easy to hard · full solution & trap analysis
The diagonals of a rhombus are 16 cm and 12 cm. Find its area.
Practice 2easy
The area of a square is 256 cm². What is the length of its side?
Practice 3easy
The perimeter of a rectangle is 56 cm. If the length is 18 cm, what is the area of the rectangle?
Practice 4easy
A parallelogram has a base of 24 cm and height of 15 cm. What is its area?
Practice 5easy
The perimeter of a rectangle is 56 cm. If its length is 18 cm, what is its breadth?
Practice 6easy
A trapezium has parallel sides of 10 cm and 14 cm, and height 8 cm. What is its area?
Practice 7easy
A rhombus has diagonals of length 16 cm and 12 cm. What is its area?
Practice 8easy
A rectangle has length 24 cm and breadth 18 cm. What is the perimeter of the rectangle?
Practice 9easy
A parallelogram has base 20 cm and height 15 cm. What is its area?
Practice 10medium
A parallelogram has adjacent sides of length 12 cm and 8 cm. If the angle between them is 60°, what is the area of the parallelogram?
Practice 11medium
A parallelogram has adjacent sides of length 12 cm and 8 cm. If the angle between these sides is 60°, what is the area of the parallelogram?
Practice 12medium
A rhombus has diagonals of length 16 cm and 12 cm. What is the perimeter of the rhombus?
Practice 13medium
In a rectangle PQRS, the length is 20 cm and the width is 15 cm. A diagonal is drawn from P to R. What is the ratio of the area of triangle PQR to the area of the rectangle PQRS?
Practice 14medium
A square has a side length of 10 cm. If a diagonal of the square is drawn, what is the ratio of the diagonal to the side of the square?
Practice 15medium
In a quadrilateral ABCD, the diagonals AC and BD intersect at point O. If AC = 20 cm, BD = 16 cm, and the diagonals are perpendicular to each other, what is the area of the quadrilateral?
Practice 16medium
A rectangle has length 15 cm and breadth 8 cm. A diagonal is drawn. What is the length of the diagonal?
Practice 17hard
In trapezoid PQRS, PQ is parallel to RS. The non-parallel sides PS and QR are equal in length (isosceles trapezoid). If PQ = 28 cm, RS = 16 cm, and the height of the trapezoid is 12 cm, find the length of the equal sides PS and QR.
60-Second Revision — Quadrilaterals
Remember: All quadrilateral interior angles sum to 360°
Formula: Area with perpendicular diagonals = (1/2) × d1 × d2
Trap: Square is both rectangle and rhombus, but rhombus is not always rectangle
Quick check: Parallelogram opposite sides are parallel AND equal
Memory aid: Rectangle = right angles, Rhombus = equal sides