Chapter 17 · Class 9 ICSE · Formula Sheet

Area of Plane Figures Formulas — Class 9 ICSE

Calculate area of triangles using Heron's formula and area of quadrilaterals and polygons.

Key Formulas

Heron's Formula

A = \sqrt{s(s-a)(s-b)(s-c)}, \quad s = \dfrac{a+b+c}{2}

CSA of Cone

\pi r l

Volume of Cone

\dfrac{1}{3}\pi r^2 h

SA of Sphere

4\pi r^2

Volume of Sphere

\dfrac{4}{3}\pi r^3

Worked Examples

1Using: Area of Rectangle

Find the area of a rectangle with length 12 cm and breadth 5 cm.

Step 1: Area = l x b

Step 2: = 12 x 5 = 60 sq. cm.

Answer: 60 sq. cm

2Using: Perimeter of Square

Find the perimeter of a square with side 8 m.

Step 1: Perimeter = 4a

Step 2: = 4 x 8 = 32 m.

Answer: 32 m

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More Class 9 ICSE Formulas

Rational & Irrational NumbersCompound InterestExpansionsFactorizationSimultaneous Linear EquationsIndices (Exponents)

Frequently Asked Questions

How many formulas are in Class 9 ICSE Area of Plane Figures?+
There are 5 formulas in the Area of Plane Figures chapter for Class 9 ICSE. Each formula is essential for solving problems in this topic.
How to remember Area of Plane Figures formulas easily?+
Practice regularly with worked examples, group related formulas together, and use SparkEd's interactive practice mode to reinforce your memory through problem-solving.
Are these Area of Plane Figures formulas enough for exams?+
Yes, these formulas cover the complete ICSE Class 9 syllabus for Area of Plane Figures. Practice applying them to different types of questions for full exam readiness.

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