Samacheer Kalvi Class 5 Maths Solutions Term 2 Chapter 1 Geometry Exercise 1.1

Question 1. Write the measures of the complementary angles of the following angles.
(i) 45°
(ii) 30°
(iii) 72°
(iv) 88°
(v) 38°
Answer:
(i) 45°: The complementary angle is found by subtracting from 90°. So, \( 90° - 45° = 45° \).
(ii) 30°: To find the complementary angle, we subtract 30° from 90°. Thus, \( 90° - 30° = 60° \).
(iii) 72°: Subtracting 72° from 90° gives the complementary angle. So, \( 90° - 72° = 18° \).
(iv) 88°: The complementary angle is obtained by subtracting 88° from 90°. This means \( 90° - 88° = 2° \).
(v) 38°: We find the complementary angle by subtracting 38° from 90°. Therefore, \( 90° - 38° = 52° \).
In simple words: Complementary angles add up to 90 degrees. To find the complementary angle for any given angle, just subtract that angle from 90 degrees.

🎯 Exam Tip: Always remember that complementary angles sum up to exactly 90 degrees. Double-check your subtraction to avoid simple calculation errors.

Question 2. Write the measures of the supplementary angles of the following angles
(i) 80°
(ii) 95°
(iii) 110°
(iv) 135°
(v) 15°
Answer:
(i) 80°: The supplementary angle is calculated by subtracting from 180°. So, \( 180° - 80° = 100° \).
(ii) 95°: To find the supplementary angle, we subtract 95° from 180°. Thus, \( 180° - 95° = 85° \).
(iii) 110°: Subtracting 110° from 180° gives the supplementary angle. So, \( 180° - 110° = 70° \).
(iv) 135°: The supplementary angle is obtained by subtracting 135° from 180°. This means \( 180° - 135° = 45° \).
(v) 15°: We find the supplementary angle by subtracting 15° from 180°. Therefore, \( 180° - 15° = 165° \).
In simple words: Supplementary angles add up to 180 degrees. To find the supplementary angle for a given angle, just subtract that angle from 180 degrees.

🎯 Exam Tip: Remember that supplementary angles form a straight line and always sum up to 180 degrees. This helps in visualizing and solving problems correctly.