Pada gambar tsb, Panjang EF adalah?

x/(14 - 8) = 3/(3 + 7)
x = 3/10 × 6
x = 1,8 cm

EF = 8 + x
EF = 9,8 cm

cara lain :
EF = ((DE × AB) + (CD × AE))/(DE + AE)
EF = ((3 × 14) + (8 × 7))/(3 + 7)
EF = 98/10
EF = 9,8 cm