# Points on a circle

• May 31st 2010, 11:29 AM
Mukilab
Points on a circle
In the diagram, take O as the centre of the circle.

P,q,R and S are points on the circle

Angle ROP=110

Calculate the angle RSP

I did 360-110
then 360-55
Then 2*(305-250)=110

rsp=110
http://i296.photobucket.com/albums/m...ab/Circles.jpg
• May 31st 2010, 11:33 AM
Unknown008
The correct way to do it is to make use of angle PQR.

From the properties of angles within a circle, we know that angle 2PQR = angle ROP

Therefore, angle PQR = 110/2 = 55

Now, from quadrilaterals inscribed within a circle, the sum of two opposite angles = 180 degrees.

Therefore, 180 - 55 = RSP

And RSP = 125 degrees
• May 31st 2010, 02:21 PM
Mukilab
Interesting, do you have a place where I can shift through all of these laws? I'm studying for an exam and I have nothing but general knowledge to draw from, not knowing half of the requirements.
• May 31st 2010, 09:39 PM
nikhil
easiest and correct method
its very easy NO NEED TO CALCULATE ANGLE PQR
angle PSR=(1/2)(angle POR in the major segment)
angle POR in the major segment =360-110=250
therfor
angle PSR=(1/2)*250=125
this is the easiest and shortest method
• Jun 1st 2010, 02:28 AM
Mukilab
Thanks but where do you get these methods? Point me towards a website, book, anything please