Chapter 6: Lines and Angles

Overview

This page provides comprehensive Chapter 6: Lines and Angles - Basic Worksheet - SJMaths. Basic level practice worksheet for Class 9 Perimeter and Area.

Basic Level Worksheet

  1. Question 1: What is the sum of the angles in a linear pair?
    Solution: The sum of angles in a linear pair is $180^\circ$.
  2. Question 2: Find the complement of an angle of $65^\circ$.
    Solution: Complement $= 90^\circ - 65^\circ = 25^\circ$.
  3. Question 3: If two lines intersect each other, what is the relation between vertically opposite angles?
    Solution: Vertically opposite angles are equal.
  4. Question 4: An angle is greater than $90^\circ$ and less than $180^\circ$. What type of angle is it?
    Solution: It is an Obtuse angle.
  5. Question 5: In $\triangle ABC$, if $\angle A = 50^\circ$ and $\angle B = 60^\circ$, find $\angle C$.
    Solution: $\angle A + \angle B + \angle C = 180^\circ$ (Angle sum property).
    $50^\circ + 60^\circ + \angle C = 180^\circ \Rightarrow 110^\circ + \angle C = 180^\circ \Rightarrow \angle C = 70^\circ$.
  6. Question 6: Find the supplement of $110^\circ$.
    Solution: Supplement $= 180^\circ - 110^\circ = 70^\circ$.
  7. Question 7: If a transversal intersects two parallel lines, then consecutive interior angles are?
    Solution: Consecutive interior angles (or co-interior angles) are supplementary (sum is $180^\circ$).
  8. Question 8: What is the measure of a complete angle?
    Solution: A complete angle measures $360^\circ$.
  9. Question 9: Can a triangle have two right angles?
    Solution: No, because the sum of two right angles is $180^\circ$, leaving $0^\circ$ for the third angle, which is not possible.
  10. Question 10: If one angle of a linear pair is acute, then what kind of angle is the other?
    Solution: The other angle must be obtuse (since sum is $180^\circ$).
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