How to find the length of an arc

Practice Questions

PSAT Math › How to find the length of an arc

Questions

Circle_120_degrees

If the area of a circle is $36\pi$ , then what is the length of the $120^\circ$ arc shown in the diagram?

Circle

In the circle above, the angle A in radians is $\frac{\pi}{4}$

What is the length of arc A?

Figure not drawn to scale.

In the figure above, circle C has a radius of 18, and the measure of angle ACB is equal to 100°. What is the perimeter of the red shaded region?