cara mencarinya gimana

OB = √13²-5² = √169-25 = √144 = 12 cm
L = d1.d2/2 = 10 × 15 / 2= 75 cm²

AB=13cm
AO=5cm (10cm÷2)
BO=[tex] \sqrt{ 13^{2} } - 5^{2} [/tex] = 12cm

Luas belah ketupat=
 d1×d2÷2
=10×(3+12)÷2
=75 cm²