Use the formula for radian measure to calculate the measure of a central angle in a circle having a radius of 12 cm and intercepting an arc of 21 cm.

The length of an arc is the product of the radius and the central angle.

The measure of the central angle is 1.75 radians

The given parameters are:

--- radius

--- the length of the arc

The length of the arc is calculated as follows:

Make the subject

Substitute known values

Divide

Express properly as

Hence, the measure of the central angle is 1.75 radians

Read more about arc lengths at:

link

1.3

step-by-step explanation:

3x2=6   9x+6

bring down the 6 on both sides

6+6=12

12= 9x

divide by 9

12/9 =

1.3 =x