Hello, MikeNoob!
We need more information . . .
How can you say that the grey triangle is isosceles?
Code:* * * * * * * * * * O * * ♥. * * *:*. * *:::*. * *:::::*. * * *:::::::♥ * *:::: * B * ♥ * A
If $\displaystyle O$ is the center of the circle,
. . then $\displaystyle OA$ and $\displaystyle OB$ are equal radii.