Determine Total Angle

Here, we’ll determine the total ANGLE of an arc if we know the RADIUS and the ARC LENGTH.

Our Radius for this exercise will be 96 inches and the arc length will be 120 inches.
Punch in 96 x ∏(3.14159) = you get 301.59. Divide this by 120. You get 2.513.
Now hit the key 1/x on your calculator, you should get .39788. Now x 180 = You get 71.62 degrees.
The total ANGLE of the arc is 71.62 degrees.

In short:

Radius x ∏ = ___ ÷ Arc Length = ___  1/x  x  180 = ANGLE.

This exercise is good for all angles of less than 180 degrees of arc.