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# Geometry - finding radius of circle.. Watch

1. A circle is circumscribed about an isosclese triangle whose sides have lengths 13, 13, and 24cm

Find the radius of the circle

a diagram wasnt given but its basically a triangle with a circle around it

I started of by finding the height of the triangle which is 5cm but i duno what to do next..

any help?

2. You are more likely to get a response here.

Anyyhow, have you heard of the extended sine rule?

Spoiler:
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the diameter of the circumcirlce is equal to the ratio of a side to the sine of an opposite angle. Combine this with the cosine rule
3. (Original post by helpmee1234567890)
A circle is circumscribed about an isosclese triangle whose sides have lengths 13, 13, and 24cm

Find the radius of the circle

a diagram wasnt given but its basically a triangle with a circle around it

I started of by finding the height of the triangle which is 5cm but i duno what to do next..

any help?

I have worked out the answer to be 16.9

If that agrees with the answer in your book, let me know and I'll send you the solution (hard to explain without showing you a drawing) but essentially it uses the fact that there's a right angled triangle in a semi-circle and pythagoras with simultaneous equations.
4. (Original post by dugdugdug)
I have worked out the answer to be 16.9

If that agrees with the answer in your book, let me know and I'll send you the solution (hard to explain without showing you a drawing) but essentially it uses the fact that there's a right angled triangle in a semi-circle and pythagoras with simultaneous equations.
Hey
yeh thats the answer I found it in the end but thanks

Updated: April 1, 2012
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