No 25, sertakan caranya

Luas segitiga = 36V3
(n/2)^2V3 = 36V3
(n/2)^2 = 36
n/2 = 6
n = 12
Jari-jari lingkaran luas segitiga,
r = (abc)/(4L_{segitiga})
r = (12^3)/(4 x 36V3)
r = (12^3)/(12^2V3)
r = 12/(V3)
r = 4V3
Sehingga panjang sisi persegi 8V3
Selisih luas persegi dan lingkaran,
= (8V3)^{2} - \pi(4V3)^2
= (4V3)^2[2^2 - \pi]
= 48(4 - \pi)

L ∆ = 36√3
1/2 . s² sin 60° = 36√3
s = 12 cm

s² = r² + r² - 2r² cos 120°
s² = 3r²
r² = 48 cm²

Selisih
= 4r² - πr²
= 48(4 - π) cm²
Opsi C.