Class 8 Maths - CBSE
Quadrilaterals
The chapter 'Quadrilaterals' in Class 8 Mathematics introduces students to 4-sided closed polygons and their fascinating geometric properties. You will learn about the angle sum property of polygons, different types of quadrilaterals like parallelograms, rectangles, squares, rhombuses, trapeziums, and kites, and their specific diagonal properties. This chapter forms the absolute foundation for geometry in higher classes and frequently appears in CBSE board exams through theorem-based proofs and calculation-heavy problems, making it a high-scoring topic if your concept of properties is crystal clear.
Start Learning FreeKey Concepts
Angle Sum Property of a Quadrilateral
The sum of all four interior angles in any quadrilateral is always equal to 360 degrees.
Parallelogram
A quadrilateral in which both pairs of opposite sides are parallel and equal, opposite angles are equal, and diagonals bisect each other.
Rhombus
A special parallelogram where all four sides are equal in length and the diagonals intersect each other at right angles (90 degrees).
Rectangle and Square
A rectangle is a parallelogram with all angles equal to 90 degrees and equal diagonals, while a square is a rectangle with all four sides equal.
Trapezium and Kite
A trapezium has one pair of parallel sides, whereas a kite is a quadrilateral with two pairs of adjacent sides that are equal in length.
Important Formulas
Board Exam Info
In CBSE Class 8 mathematics assessments, this chapter typically carries around 6 to 8 marks. Questions frequently include finding unknown angles using the angle sum property, proving properties of parallelograms, and identifying special quadrilaterals based on given side lengths or diagonal properties.
Frequently Asked Questions
Are all squares also rhombuses and rectangles?
Yes! A square is a special type of rhombus because all its sides are equal, and it is also a rectangle because all its interior angles are 90 degrees.
Do the diagonals of a parallelogram always bisect each other at 90 degrees?
No. While the diagonals of a parallelogram bisect each other, they only intersect at 90 degrees in a rhombus and a square.
How do I find the sum of interior angles for a polygon with many sides?
You can use the formula (n - 2) * 180 degrees, where 'n' represents the total number of sides in the polygon.
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