abcd = belah ketupat.kelilingnya = 68 cm dan diagonal BD = 16 cm luas belah ketupat abcd adalah.......cm²

keliling belah ketupat = 68
4s = 68
s = 68/4 = 17 cm

panjang diagonal BD = 16 ,(O tengah2 diagonal BD,maka BO = 16/2 = 8 cm)
panjang diagonal yang lain:
AO = √17^2 - 8^2
AO = √289 - 64
AO = √225
AO = 15 cm
AC = AO+OC = 15 + 15 = 30 cm

L = 1/2 x d1 x d2
L = 1/2 x 16 x 30
L = 240 cm^2