1. If the 15-inch wiper rotated 360°, its tip would cover a path equal to the circumference of the circle formed.
2. The circumference C=2[tex] \pi [/tex]r=2*3.14*15=94.2 in. The angle actually covered by the tip forms only a fraction of this length, that is 36 inch.
3. Let α be the angle of rotation of the tip
360° -------- 94.2 in
x -------- 36 in
so x=[tex] \frac{360*36}{94.2}= 137.6[/tex] degrees
