Ini gimana caranya ya,,, mentok

Misal sisi persegi OCDE = x
OC = OE = ED = DC = x
OB = 6 => BE = 6 - x

Dengan kesebangunan
ED/OA = BE/BO
x/12 = (6 - x)/6
6x = 12(6 - x)
6x = 72 - 12x
18x = 72
x = 4
Luas OCDE = x . x = 4 . 4 = 16 cm^2

Kesebangunan.

OC = CD = DE = OE = a

OA / ED = OB / BE
OA / a = OB / (OB - a)
(OB - a) / a = OB / OA
(6 - a) / a = 6 / 12
(6 - a) / a = 1 / 2
a = 12 - 2a → a = 4 cm

L OCDE = (4 cm)² = 16 cm²