The triangle in the figure below is circumscribed by a circle with radius .

Find the value of .

Any triangle can be circumscribed by a circle.

Find a formula for the radius of the circle, given the three sides of the triangle.

Show that, if you haven’t already done so, that .

Find a similar expression for using angle and side ; then angle and side . Hence prove the sine rule.

Done here! Take me back to the triangles menu.