Name: Marko

Who is asking: Student Level: Secondary

Question: In a circle of radius 6, a triangle PQR is drawn having QR = 8 and PQ = 10. Determine the length of PR

Hi Marko,

In the diagram below, t is the angle measurement of angle RCQ where C is the center of the circle. Use the Law of Cosines with triangle CQR to find

cos(t) = 72-64/721/9

The angle RPQ has angle measurement  t/2 and hence

Let x be the length of the side RP then, using the Law of Cosines with triangle RPQ,

The general quadratic can now be used to find x.

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