SOLUTION: A chord 8mm long is formed by an angle of 45degrees subtended at the centre of a circle. Find the radius of the circle.

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Question 1138233: A chord 8mm long is formed by an angle of 45degrees subtended at the centre of a circle. Find the radius of the circle.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Isosceles Triangle, angles 45, 22.5, 22.5 degrees;
The side 8 mm is opposite the 45 degree angle.
You want length of either of the congruent sides.
Use Law Of Sines, unless you can find another way.

in case it helps, 22.5 degrees is pi%2F8.
sin%28pi%2F8%29=sqrt%282-sqrt%282%29%29%2F2.

You already know sin%28pi%2F4%29=sqrt%282%29%2F2.

Radius:
%28%28sqrt%282-sqrt%282%29%29%29%2F2%29%2816%2Fsqrt%282%29%29

4%2Asqrt%282%29%2Asqrt%282-sqrt%282%29%29