Page No 94:
Question 1:
Match the following:(i) Straight angle (a) Less than one-fourth of a revolution
(ii) Right angle (b) More than half a revolution
(iii) Acute angle (c) Half of a revolution
(iv) Obtuse angle (d) One-fourth of a revolution
(v) Reflex angle (e) Between
of a revolution(f) One complete revolution
Answer:
(i) Straight angle is of 180º and half of a revolution is 180º.Hence, (i) ↔ (c)
(ii) Right angle is of 90º and one-fourth of a revolution is 90º.
Hence, (ii) ↔ (d)
(iii) Acute angles are the angles less than 90º. Also, less than one-fourth of a revolution is the angle less than 90º.
Hence, (iii) ↔ (a)
(iv) Obtuse angles are the angles greater than 90º but less than 180º. Also, between
of a revolution is the angle whose measure lies between 90º and 180º.Hence, (iv) ↔ (e)
(v) Reflex angles are the angles greater than 180º but less than 360º. Also, more than half a revolution is the angle whose measure is greater than 180º.
Hence, (v) ↔ (b)
Page No 95:
Question 2:
Classify each one of the following angles as right, straight, acute, obtuse or reflex:
Answer:
(a) Acute angle as its measure is less than 90º.(b) Obtuse angle as its measure is more than 90º but less than 180º.
(c) Right angle as its measure is 90º.
(d) Reflex angle as its measure is more than 180º but less than 360º.
(e) Straight angle as its measure is 180º.
(f) Acute angle as its measure is less than 90º .
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