α = d/4

β = 3d/8

γ = 2d/3

δ = d/2

Все 4 угла вместе дают развёрнутый угол

α + β + γ + δ = 180°

d/4 + 3d/8 + 2d/3 + d/2 = 180

d(1/4 + 3/8 + 2/3 + 1/2) = 180

d(2/8 + 3/8 + 2/3 + 4/8) = 180

d(9/8 + 2/3) = 180

d(27/24 + 16/24) = 180

d*43/24 = 180

d = 4320/43

А сами углы

α = d/4 = 4320/43*1/4 = 1080/43 = 25 5/43°

β = 3d/8 = 4320/43*3/8 = 1620/43 = 37 29/43°

γ = 2d/3 = 2880/43 = 66 42/43°

δ = d/2 = 4320/43*1/2 = 2160/43 = 50 10/43°