**Determine if the following ratios form a proportion. Also, write the middle terms and extreme terms where the ratios form a proportion.**

**(a)** 25 cm : 1 m and Rs 40 : Rs 160

**(b)** 39 liters : 65 liters and 6 bottles : 10 bottles

**(c)** 2 kg : 80 kg and 25 g : 625 g

**(d)** 200 ml : 2.5 liters and Rs 4 : Rs 50

**(a)** 25 cm : 1 m and Rs 40 : Rs 160

25 cm : 1 m = 25 cm : 100 cm

Rs 40 : Rs 160

Therefore, they are in proportion. Middle terms are 1 m and Rs 40. Extreme terms are 25 cm and Rs 160.

**(b)** 39 liters : 65 liters and 6 bottles : 10 bottles

39 liters : 65 liters

6 bottles : 10 bottles

Therefore, they are in proportion. Middle terms are 65 liters and 6 bottles. Extreme terms are 39 liters and 10 bottles.

**(c)** 2 kg : 80 kg and 25 g : 625 g

2 kg : 80 kg

25 g : 625 g

Therefore, they are not in proportion.

**(d)** 200 ml : 2.5 liters and Rs 4 : Rs 50

200 ml : 2.5 liters = 200 ml : 2500 ml

Rs 4 : Rs 50

Therefore, they are in proportion. Middle terms are 2.5 liters and Rs 4. Extreme terms are 200 ml and Rs 50.