(ii) sin 71^o 31′

Solution:-

To find the value of sin 71^o 31’,

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

In the vertical column headed by 31’ i.e. 31’ – 30’ = 1’ in the difference column, the value of 1’ in mean difference column is 1.

Then, value that we find in vertical column is 0.9483

Now adding the value of 30’ and 1’ = 0.9483 + 1

= 0.9484

Therefore, the value of sin 71^o 31’ is obtained as under,

sin 71^o 31’ = 0.9483 … [from table]

Mean difference for 1’ = 1 … [to be added]

Then, sin 71^o 31’ = 0.9484