Top 10.125

BAC = ACB = α = 36°

MAX ( AB ) = 3.23624406466

Angle CAD = 56

AB = ϕ = 1.61803398875

Radius R = D₂ = 0.8 = 4 / 5

R = 4 ⇒ X = LT = 4

180 X = 72 ⇒ X = 2 / 5 = 0.4

Shaded Area = 9 / 2 = 4.5

Angle GOJ = 150°

Orange Area = ( X ⋅ Y ) / 2