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## Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 6 Trigonometry Ex 6.4

Question 1.

Find the value of the following :

(i) sin 49°

(ii) cos 74° 39′

(iii) tan 54° 26′

(iv) sin 21° 21′

(v) cos 33° 53′

(vi) tan 70° 17′

Solution:

Question 2.

Find the value of θ if

(i) sin θ = 0.9975

(ii) cos θ = 0.6763

(iii) tan θ = 0.0720

(iv) cos θ = 0.0410

(v) tan θ = 7.5958

Solution:

(i) From the natural sines table

Question 3.

Find the value of the following :

(i) sin 65° 39′ + cos 24° 57′

(ii) tan 70° 58′ + cos 15° 26′ – sin 84° 59′

Solution:

(i) = 0.9111 + 0.9066 + 0.1793 = 1.9970

(ii) = 2.8982 + 0.9639 – 0.9962 = 3.8621 – 0.9962 = 2.8659

Question 4.

Find the area of a right triangle whose hypotenuse is 10cm and one of the acute angle is 24° 24′

Solution:

Question 5.

Find the angle made by a ladder of length 5m with the ground, if one of its end is

4m away from the wall and the other end is on the wall.

Solution:

Question 6.

In the given figure, HT shows the height of a tree standing vertically. From a point P, the angle of elevation of the top of the tree (that is ∠P) measures 42° and the distance to the tree is 60 metres. Find the height of the tree.

Solution: