# A triangle in a circle

- Author:
- Casper Buisman

- Topic:
- Circle

Let's draw a circle with a certain radius. We inscribe a triangle with one side being the diameter of the circle. The opposite angle will be 90 degrees according to Thales (semi circle theorem).
Now divide the diameter by the Sine of it's opposite (90 degree) angle. What number do you get?
Also divide the other side lengths by the sine of their opposite angle. What's the answer?
Will this also work for triangles that are not on the diameter of the circle?
Hint: Sin(90) = 1 i.e. the sine of 90 degrees is 1.

## New Resources

## Discover Resources

Download our apps here: