The first step is to draw an equilateral triangle. This will fit inside a circle divided in 3 x 120 degree angles.
Next duplicate the triangle and resize the duplicate to half the height (in proportion). Duplicate the small triangle twice more, and put one in each corner of the larger triangle.
Next duplicate the blue triangle and resize this duplicate to half the height (in proportion) and colour in contrast. Duplicate the small triangle twice more, and put one in each corner of the larger triangle. . . . repeat as many times as you like.