# Probability and inscribed angle.

• Apr 22nd 2010, 05:48 PM
takersgirl007
Probability and inscribed angle.
See attachment.

Probability:

In $\displaystyle \odot$V, point C is randomly located so that it does not coinside with points R or S. If $\displaystyle m\widehat{RS}=140$, what is the probability that $\displaystyle m\angle RCS=70$?

• Apr 23rd 2010, 09:25 AM
masters
Quote:

Originally Posted by takersgirl007
See attachment.

Probability:

In $\displaystyle \odot$V, point C is randomly located so that it does not coinside with points R or S. If $\displaystyle m\widehat{RS}=140$, what is the probability that $\displaystyle m\angle RCS=70$?

Hi takersgirl007,

If you randomly position point C between points R and S such that angle C is always 70 degrees, you will always intercept an arc of 140 degrees.

You have 220 degrees of arc on which to place point C (360 - 140 =220).

The probability then would be $\displaystyle \frac{220}{360} \:or\: \frac{11}{18}$
• Apr 23rd 2010, 05:41 PM
takersgirl007
Thank you so much! :)

I was totally lost on this one..