(iii) sin 65^o 20′

Solution:-

To find the value of sin 65^o 20’,

We read the table of natural sines in the horizontal line which begins with 35^o

In the vertical column headed by 20’ i.e. 20’ – 18’ = 2’ in the difference column, the value of 2’ in mean difference column is 2.

Then, value that we find in vertical column is 0.9085

Now adding the value of 18’ and 2’ = 0.9085 + 2

= 0.9087

Therefore, the value of sin 65^o 20’ is obtained as under,

sin 65^o 20’ = 0.0985 … [from table]

Mean difference for 2’ = 2 … [to be added]

Then, sin 65^o 20’ = 0.9087