Find the mean proportion between :

(i) 81 and 121

(ii) 1.8 and 0.2

(iii) $\dfrac{2}{3}$ and $\dfrac{8}{27}$

(iv) 0.32 and 0.08

(v) $\dfrac{1}{25}$ and $\dfrac{1}{16}$

Find the third proportional to :

(i) 36, 12

(ii) 1.2, 0.6

(iii) $\dfrac{1}{9}, \dfrac{2}{3}$

(iv) 1m 60 cm, 40 cm

(v) 1 kg 250 g, 500 g

(vi) ₹ 2.40, ₹ 4.80

If 8 pens cost ₹ 356, what is the cost of 14 pens?

A uniform iron bar of length 7 m weighs 22.4 kg. How much does the same bar of length 13 m weigh ?