Chapter 5: Understanding Elementary Shapes

(i) Straight angle = 180⁰ or half of a revolution

Hence, (c) is correct answer

(ii) Right angle = 90⁰ or one-fourth of a revolution

Hence, (d) is correct answer

(iii) Acute angle = less than 90⁰ or less than one-fourth of a revolution

Hence, (a) is correct answer

(iv) Obtuse angle = more than 90⁰ but less than 180⁰ or between 1 / 4 and 1 / 2 of a revolution

Hence, (e) is correct answer

(v) Reflex angle = more than 180⁰ but less than 360⁰ or more than half a revolution

Hence, (b) is correct answer

(i) The given angle is acute angle it measures less than 90⁰

(ii) The given angle is obtuse angle as it measures more than 90⁰ but less than 180⁰

(iii) The given angle is right angle as it measures 90⁰

(iv) The given angle is reflex angle as it measures more than 180⁰ but less than 360⁰

(v) The given angle is straight angle as it measures 180⁰

(vi) The given angle is acute angle as it measures less than 90⁰