**MACHINE SHOP CALCULATION - OD1640 - LESSON 2/TASK 3**

0.96923 on the page marked 75,, at the bottom (see Table 8). In this case,

the minutes are found in the extreme right-hand column. The value of the

minutes corresponding to the number 0.96923 is 45'.

Therefore, angle A =

75,, 45'.

EXAMPLE

Find the value of angle A when cos A = 0.86603.

SOLUTION

According to the preceding note, angle A must be less than 45,,. The number

0.86603 is found at the 30,, column marked "cosine" at the top (Table 9 on

the following page). The value of the minutes, in the left-hand column, is

found to be zero. Therefore, angle A = 30,, 0'.

TABLE 8.

TRIGONOMETRIC TABLE.

EXAMPLE

Find the value of angle A when tan A = 0.18384.

SOLUTION

Evidently angle A is less than 45,,. Therefore, the number 0.18384 is found

in the "tangent" column with the heading at the top of the 10,, page (Table

10 on the following page). The value of the minutes in the left-hand column

is found to be 25,,. Therefore, angle A = 10,, 25'

**66**