posted by kourtney on .
A belt wrapped tightly around cicle O forms a 60 degree angle at P, a point outside the circle. Find the length of the belt if cicle O has a radius of 9.
That's kind of hard to imagine, but it seems to me you just plug 9 in into the formula... Please clarify if I'm wrong.
A belt wrapped tightly around cicle O forms a 60 degree angle at P, a point outside the cicle. Find the length of the belt if the cicle O has a radius of 9.
diagram looks like a cicle with two tangent lines joining at point P outside the cicle. looks like a ice cream cone.
Lines from the points of contact of a tangent to the center of the circle are at right angles to the tangent.
Draw triangles connecting a tangent point, P and the center of the circle. This will form two 30-60-90 right triangles.
The angle subtended by the belt from the center of the circle is 120 degrees.
The length of the belt is (2/3)*pi*R