The tip of a 12-inch wiper blade wipes a path that is 30 inches long. What is the angle of rotation of the blade in radians to the nearest tenth? 0.4 radians 1.3 radians 2.5 radians 5.0 radians

The answer is 2.5 radians, I know, I just took the test and got it correct

Circumference of a circle is given by:

C=theta/360 πd

given that:

d=24 inches

C=30 inches

therefore;

30=Θ/360*π*24

thus;

30=0.21Θ

thus;

Θ=143.24

converting this into radians we proceed as follows;

radians = (π/180) * degrees

= (π/180) * 143.24

=2.5 radians

The answer is 2.5 radians