Calculte the third side of a isosceles triangle and the height of a radius

For the edification of all, I will bring my PM response out here in public. As with most trig questions, the unit circle is key to finding the solutions.
Wikipedia's unit circle page: https://en.wikipedia.org/wiki/Unit_circle
I will also point to this spreadsheet I built to illustrate the unit circle: http://www.excelforum.com/tips-and-t...han-excel.html
If you draw a radius through C1 (the sagitta), then you should be able to the trig functions that relate to this problem on the unit circle. Referring to Wikipedia's unit circle diagram, you are looking for AB and CD. It should be obvious that AB is twice AC and AC is simply sin(theta). CD is versine(theta) (I'll let you follow the link to versine to see how it is calculated in terms of the cos() function).