Chapter 7 · Class 9 CBSE · Formula Sheet

Triangles Formulas — Class 9 CBSE

Study congruence rules, properties of isosceles triangles, and inequalities in triangles.

Key Formulas

SSS Congruence

\text{Three sides equal}

SAS Congruence

\text{Two sides and included angle equal}

ASA Congruence

\text{Two angles and included side equal}

AAS Congruence

\text{Two angles and a non-included side equal}

RHS Congruence

\text{Right angle, hypotenuse, and one side equal}

Worked Examples

1Using: Supplementary Angles

If one angle is 65 degrees, find its supplement.

Step 1: Supplement = 180 - 65

Step 2: = 115 degrees.

Answer: 115 degrees

2Using: Vertically Opposite

Two lines intersect. If one angle is 40 degrees, find the vertically opposite angle.

Step 1: Vertically opposite angles are equal.

Step 2: The angle = 40 degrees.

Answer: 40 degrees

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More Class 9 CBSE Formulas

Number SystemsPolynomialsCoordinate GeometryLinear Equations in Two VariablesIntroduction to Euclid's GeometryLines & Angles

Frequently Asked Questions

How many formulas are in Class 9 CBSE Triangles?+
There are 5 formulas in the Triangles chapter for Class 9 CBSE. Each formula is essential for solving problems in this topic.
How to remember Triangles 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 Triangles formulas enough for exams?+
Yes, these formulas cover the complete CBSE Class 9 syllabus for Triangles. Practice applying them to different types of questions for full exam readiness.

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