# Circle

• December 11th 2009, 04:56 AM
reiward
Circle
The angle between a tangent and a chord is 14degrees19'16''. If the length of the arc subtended by the chord is 5cm, what is the radius of the circle.

Help please, I really have no idea. Can you show it with illustrations, thanks! :)
• December 11th 2009, 06:41 AM
Quote:

Originally Posted by reiward
The angle between a tangent and a chord is 14degrees19'16''. If the length of the arc subtended by the chord is 5cm, what is the radius of the circle.

Help please, I really have no idea. Can you show it with illustrations, thanks! :)

HI

take a look at the diagram i attached .

s=5 , r=?? , $\theta=??$

Remember these 2 properties of circle

(1) angles of alternate segment are equal (red)

(2) angles at radius is twice the angle at circumference (blue)

Then use this formula , $s=r\theta$ to get r .