In triangle ABC, P and Q are the mid points of AB and AC, respectively. R is a point on PQ such that PR : RQ = 3 : 5 and QR = 20 cm, then what is the length (in cm) of BC?
Answer & explanation
Correct answer: option 3
Let the length of PQ be x
PR : RQ = 3 : 5
x × \(\frac{5}{8}\) = 20
= x = 20 × \(\frac{8}{5}\) = 32 cm.
PQ = 32 cm
PQ = \(\frac{1}{2}\)BC
= BC = 2 x PQ
= BC = 2 x 32 = 64 cm.
Therefore, length of BC is 64 cm.