West Bengal Board Class 10 Math Solution Chapter 20 - Trigonometry: Concept of Measurement of Angle

Let us express the following into degrees, minutes and seconds.

(i) 832’ (ii) 6312’’

Let us determine the circular values of the followings

(i) 60° (ii) 135°

(ii) -150° (iv) 72°

(v) 22°30’ (vi) -62°30’

(vii) 52°52’30’’

In ΔABC, AC=BC and BC is extended upto the point D. If ∠ACD=144°, then let us determine the circular value of each of the angles of ΔABC.

If the difference of two acute angles of a right-angled triangle is , then let us write the sexagesimal values of two angles.

The measure of one angle of a triangle is 65° and other angle is ; let us write the sexagesimal value and circular value of third angle.

If the sum of two angles is 135° and their difference is ; then let us determine the sexagesimal value and circular value of two angles.

If the ratio of three angles of a triangle is 2:3:4, then let us determine the circular value of the greatest angle.

The length of a radius of a circle is 28 cm. Let us determine the circular value of angle subtended by an arc of 5.5 cm length at the centre of this circle.

The ratio of two angles subtended by two arcs of unequal lengths at the centre is 5:2 and if the sexagesimal value of the second angle is 30°. Then let us determine the sexagesimal value and the circular value of the first angle.

A rotating ray makes an angle π. Let us write by calculating, in which direction the ray has completely rotate and there after what more angle it has produced.