Question

In a trapezium (ABCD), (AB ∥ CD), the diagonal (AC) and (BD) intersect at (O). If (OC = 3) cm, (OB = 2) cm, and (OA = 4) cm, then find the length of side (OD).
a) 5 cm
b) 7 cm
c) 8 cm
d) 6 cm