Answer:
Here, BRX and NJY are two triangles in which,
BR = 30 cm, RX = 40 cm, BX = 60 cm, NJ = 15 cm, JY = 20 cm and NY = 30 cm,
Also, m∠B = m∠N, m∠R = m∠J and m∠X = m∠Y,
By the property of congruence,
,
and 
Thus, By AAA similarity postulate,

Hence, proved.