tentukan luas belah ketupat jika diketahui keliling nya 80 cm dan panjang salah satu diagonalnya 24 cm.

K = 4s
80 = 4s
s = 80/4
s = 20 cm

1/2.d2 = √s² - (1/2.d1)²
1/2.d2 = √20² - (24:2)²
1/2.d2 = √400 - 12²
1/2.d2 = √400 - 144
1/2.d2 = √256
d2 = 16 × 2
d2 = 32 cm

L = d1 × d2/2
L = 24 × 32/2
L = 24 × 16
L = 384 cm²