Karnataka 1st PUC Maths Chapter 9 Important Questions 2026-27: Straight Lines

Karnataka 1st PUC Maths Chapter 9 Important Questions help students revise Straight Lines, an important topic in coordinate geometry. The chapter covers slopes, equations of lines, angles between lines, and different forms of linear equations. 

Practising these questions helps students strengthen their concepts, improve calculation accuracy, and prepare for examinations. Students should also review the Karnataka 1st PUC Syllabus 2026-27 to understand the prescribed curriculum and plan their preparation.

Karnataka 1st PUC Maths Chapter 9 Important Questions PDF

Students can practise questions using the official chapter-wise PDF provided for Straight Lines. It can help them revise important concepts and practise problems based on the chapter.

Students should solve the questions independently and revise the relevant formulas whenever they encounter difficulties. Checking the Karnataka 1st PUC Exam Pattern 2026-27 can also help them understand the examination structure and plan their revision.

Karnataka 1st PUC Maths Chapter 9 Important Questions: Straight Lines

The Straight Lines chapter introduces essential coordinate geometry concepts. Students should practise different question types to understand how formulas are applied to numerical problems.

1. Slope of a Straight Line

The slope represents the inclination of a line with respect to the positive direction of the x-axis. Students should understand how to calculate the slope using the coordinates of two points.

Important question types include:

• Find the slope of a line passing through two given points.

• Calculate the angle of inclination when the slope is known.

• Determine the slope of a line parallel or perpendicular to another line.

• Find an unknown coordinate when the slope is given.

2. Equation of a Straight Line

Students should practise writing equations of lines using different forms, depending on the information provided in a question.

Important question types include:

• Find the equation of a line passing through a point with a given slope.

• Find the equation of a line passing through two points.

• Write the equation in slope-intercept form.

• Find the equation of a line using its x-intercept and y-intercept.

Regular practice helps students select the appropriate formula and solve questions accurately.

3. Angle Between Two Straight Lines

This topic involves calculating the angle between two lines using their slopes.

Practise questions based on finding the angle between two lines, identifying parallel or perpendicular lines, and calculating an unknown slope when the angle is given.

4. Different Forms of a Straight-Line Equation

Students should revise the point-slope form, two-point form, slope-intercept form, intercept form, and general form of a straight-line equation. Understanding these forms helps students solve questions efficiently.

Karnataka 1st PUC Maths Chapter 9 Important Questions with Answers: Practice Set

Practise the following questions to revise the main concepts of Straight Lines.

1. The slope of the line which makes 45° with positive x-axis measured anticlockwise is:

(A) −1 (B) 1 (C) 0 (D) Not defined

2. The slope of the line which makes 4 with positive y-axis measured anticlockwise is:

(A) −1 (B) 1 (C) 0 (D) Not defined

3. The angle of inclination with respect to positive x-axis, of the line with slope −1 is:

(A) −1° (B) 1° (C) 4 (D) 34

4. The line if its slope is zero is:

(A) Either the line is y-axis or it is parallel to y-axis (B) θ is an obtuse angle (C) Either the line is x-axis or it is parallel to x-axis (D) θ is an acute angle

5. The slope of the line through the points (3, −2) and (−1, 4) is:

(A) 23 (B) 32 (C) -32 (D) Not defined

6. The slope of the line through the points (3, −2) and (3, 4) is:

(A) 0 (B) 4 (C) −1 (D) Not defined

7. Line through the points (−2, 6) and (4, 8) is parallel to the line through the points (8, 12) and (x, 24). Then the value of x is:

(A) 0 (B) 4 (C) −1 (D) 44

8. Line through the points (−2, 6) and (4, 8) is perpendicular to the line through the points (8, 12) and (x, 24). Then the value of x is:

(A) 0 (B) 4 (C) −1 (D) 44

9. The slope of the line which makes an angle of 30° with the positive direction of the y-axis measured anticlockwise is:

(A) 3 (B) -3 (C) 1 (D) 13

10. If three points (h, 0), (a, b) and (0, k) lie on a line, then:

(A) ah+bk=1 (B) ah-bk=1 (C) ha+kb=1 (D) ha-kb=1

Students should show their calculations and verify their answers after solving each question. For further practice, they can use the Karnataka 1st PUC Maths Model Papers 2026-27 to practise examination-style problems.

How to Prepare for Karnataka 1st PUC Maths Chapter 9

Prepare for Karnataka 1st PUC Maths Chapter 9 by following these five steps to strengthen your concepts, practise important questions, and improve exam performance.

1. Revise important formulas for slopes and equations of straight lines.

2. Solve textbook examples to understand basic concepts.

3. Practise important questions and numerical problems regularly.

4. Solve the Karnataka 1st PUC Mid Term Question Papers With Answer Key.

5. Practise under timed conditions to improve accuracy and time management.

Preparing for Karnataka 1st PUC Maths Chapter 9 becomes easier with regular practice and formula revision. Focus on understanding straight-line concepts, solving important questions, and practising previous question papers to improve accuracy, confidence, and overall exam performance.