Chapter 6 · Class 9 CBSE · Formula Sheet

Lines & Angles Formulas — Class 9 CBSE

Prove and apply theorems on linear pairs, vertically opposite angles, and parallel line transversals.

Key Formulas

Linear Pair

\angle 1 + \angle 2 = 180°

Vertically Opposite

\angle 1 = \angle 3

Angles of a Triangle

\angle A + \angle B + \angle C = 180°

Exterior Angle

\text{Exterior angle} = \text{Sum of remote interior angles}

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 Systems Polynomials Coordinate Geometry Linear Equations in Two Variables Introduction to Euclid's Geometry Triangles

Frequently Asked Questions

How many formulas are in Class 9 CBSE Lines & Angles?+

There are 4 formulas in the Lines & Angles chapter for Class 9 CBSE. Each formula is essential for solving problems in this topic.

How to remember Lines & Angles 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 Lines & Angles formulas enough for exams?+

Yes, these formulas cover the complete CBSE Class 9 syllabus for Lines & Angles. Practice applying them to different types of questions for full exam readiness.

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