Skip to main content
Chapter 4 of 15
Flashcards

Lines and Angles

Kerala Board · Class 9 · Mathematics

Flashcards for Lines and Angles — Kerala Board Class 9 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

45 questions20 flashcards5 concepts
20 Flashcards
Card 1Pairs of Angles

Find the complementary angle of 35°

Answer

Step 1: Recall that complementary angles sum to 90° Step 2: Let the complementary angle be x Step 3: Set up equation: 35° + x = 90° Step 4: Solve: x = 90° - 35° = 55° Answer: 55°

Card 2Pairs of Angles

Two supplementary angles are in the ratio 3:7. Find both angles.

Answer

Step 1: Let the angles be 3x and 7x Step 2: Since supplementary angles sum to 180°: 3x + 7x = 180° Step 3: Combine: 10x = 180° Step 4: Solve: x = 18° Step 5: Find angles: 3x = 3(18°) = 54°, 7x = 7(18°

Card 3Intersecting Lines

In intersecting lines, if one angle is 65°, find all four angles formed.

Answer

Step 1: Vertically opposite angles are equal Step 2: Given angle = 65° Step 3: Vertically opposite angle = 65° Step 4: Adjacent angles are supplementary (sum = 180°) Step 5: Other two angles = 180° -

Card 4Parallel Lines and Transversals

If two parallel lines are cut by a transversal and one angle is 110°, find the corresponding angle.

Answer

Step 1: Recall corresponding angles axiom Step 2: When parallel lines are cut by a transversal, corresponding angles are equal Step 3: Given angle = 110° Step 4: Corresponding angle = 110° Answer: 110

Card 5Parallel Lines and Transversals

Two parallel lines cut by transversal form alternate interior angles of (3x + 15)° and (2x + 40)°. Find x.

Answer

Step 1: Alternate interior angles are equal when lines are parallel Step 2: Set up equation: 3x + 15 = 2x + 40 Step 3: Subtract 2x from both sides: x + 15 = 40 Step 4: Subtract 15 from both sides: x =

Card 6Triangle Angle Sum

Find the sum of angles in triangle ABC where ∠A = 60° and ∠B = 45°

Answer

Step 1: Use angle sum property: ∠A + ∠B + ∠C = 180° Step 2: Substitute known values: 60° + 45° + ∠C = 180° Step 3: Simplify: 105° + ∠C = 180° Step 4: Solve for ∠C: ∠C = 180° - 105° = 75° Step 5: Verif

Card 7Triangle Angle Sum

In triangle PQR, angles are in ratio 2:3:4. Find all three angles.

Answer

Step 1: Let angles be 2x, 3x, and 4x Step 2: Use angle sum property: 2x + 3x + 4x = 180° Step 3: Combine: 9x = 180° Step 4: Solve: x = 20° Step 5: Find angles: 2x = 40°, 3x = 60°, 4x = 80° Step 6: Ver

Card 8Exterior Angles

Find the exterior angle of a triangle if two interior opposite angles are 35° and 48°

Answer

Step 1: Use exterior angle theorem Step 2: Exterior angle = Sum of two interior opposite angles Step 3: Exterior angle = 35° + 48° Step 4: Exterior angle = 83° Step 5: Verify: Third interior angle = 1

+12 more flashcards available

Practice All

Get detailed flashcards for Lines and Angles

Super Tutor gives you interactive content for every chapter of Kerala Board Class 9 Mathematics — summaries, quizzes, flashcards, and more.

Try Super Tutor — It's Free

Frequently Asked Questions

What are the important topics in Lines and Angles for Kerala Board Class 9 Mathematics?

Lines and Angles covers several key topics that are frequently asked in Kerala Board Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

There are 20 flashcards for Lines and Angles covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.