You can say since the center of the shape(?) U has 3 lines extending to the edges of the shape, the sides of the radii must be the same as well as the sides of all the triangles.
Imagine a hexagon with 6 triangles basically, all the sides are the same and consist of mainly the same angle measurements
Imagine a hexagon with 6 triangles basically, all the sides are the same and consist of mainly the same angle measurements


If you need anything cleared I can tell you what it is if my paint writing is that bad. The numbers are angle measures.