Class 7 · Chapter 11

Perimeter and Area

Perimeter and area of squares, rectangles, triangles, parallelograms and circles.

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Tip: open the NCERT PDF for the original chapter text alongside the notes here.

Detailed theory

Area

=

base

\times

height (perpendicular distance between parallel sides). Not the same as base × side.

Key concepts & formulas

Area of rectangle

= l \times b

Area of triangle

= \tfrac{1}{2}\text{base}\times\text{height}

Area of parallelogram

= \text{base}\times\text{height}

Circumference of circle

= 2\pi r

; area

= \pi r^2

1

^2

= 10000

^2