Diketahui persegi ABCD dengan panjang diagonal AC = (4x - 9) cm dan BD = (2x + 3) cm. Luas persegi ABCD adalah... a. 225 cm2 b. 112,5 cm2 c. 81 cm2 d. 40,5 c

diagonal diagonal persegi sama panjang
jadi AC = BD
4x-9 = 2x+3
2x = 12
x= 6 cm
BD = 2x+3 = 2x6 + 3 = 12+3 = 15 cm

rumus luas = d^2/2
= 15^2/2 = 225/2 = 112,5cm^2 (B)

Langsung aja y

AC = BD
4x - 9 = 2x + 3
4x - 2x = 3 + 9
x = 12 : 2
x = 6

AC = 4(6) - 9 = 15 cm
BD = 2(6) + 3 = 15 cm

AC = s√2
s√2 = AC
s = 15 : √2
s = 7,5 √2 cm

L = s²
L = (7,5√2)²
L = 7,5² × √2²
L = 56,25 × 2
L = 112,5 cm²

jawabannya B

semoga berguna +_+