Exercise 12.2
1. Determine if the following are in proportion.
(a - c)
(a) 15, 45, 40, 120
Ratio =
Ratio =
Hence 15:45
Therefore 15, 45, 40, 120 are
(b) 33, 121, 9,96
Ratio =
Ratio =
Hence 33:121
Therefore 15, 45, 40, 120 are
(c) 24, 28, 36, 48
Ratio =
Ratio =
Hence 24:28
Therefore 24, 28, 36, 48 are
(d - f)
(d) 32, 48, 70, 210
Ratio =
Ratio =
Hence 32:48
Therefore 32, 48, 70, 210 are
(e) 4, 6, 8, 12
Ratio =
Ratio =
Hence 4:6
Therefore 4, 6, 8, 12 are
(f)33, 44, 75, 100
Ratio =
Ratio =
Hence 33:44
Therefore 33, 44, 75, 100 are
2. Write True (T) or False (F) against each of the following statements.
(a - c)
(a) 16 : 24 :: 20 : 30
Product of the extreme terms = 16 × 30 =
Product of the middle terms = 24 × 20 =
∴ The given statement is
(b) 21: 6 :: 35 : 10
Product of the extreme terms = 21 × 10 =
Product of the middle terms = 6 × 35 =
∴ The given statement is
(c) 12 : 18 :: 28 : 12
Product of the extreme terms = 12 × 12 =
Product of the middle terms = 18 × 28 =
∴ The given statement is
(d - f)
(d) 8 : 9 :: 24 : 27
Product of the extreme terms = 8 × 27 =
The product of the middle terms = 9 × 24 =
∴ The given statement is
(e) 5.2 : 3.9 :: 3 : 4
Product of the extreme terms = 5.2 × 4 =
Product of the middle terms = 3.9 × 3 =
∴ The given statement is
(f) 0.9 : 0.36 :: 10 : 4
Product of the extreme terms = 0.9 × 4 =
Product of the middle terms = 0.36 × 10 =
∴ The given statement is
3. Are the following statements true?
(a) 40 persons : 200 persons = ₹ 15 : ₹ 75
40 : 200 =
15 : 75 =
Statement is
(b) 7.5 litres : 15 litres = 5 kg : 10 kg
7.5 : 15 =
5 : 10 =
Statement is
(c) 99 kg : 45 kg = ₹ 44 : ₹ 20
99 : 45 =
44 : 20 =
Statement is
(d) 32 m : 64 m = 6 sec : 12 sec
32 : 64 =
6 : 12 =
Statement is
(e) 45 km : 60 km = 12 hours : 15 hours
45 : 60 =
12 : 15 =
Statement is
4. Determine if the following ratios form proportion. Also, write the middle terms and extreme terms where the ratios form a proportion.
(a) 25 cm : 1 m and ₹ 40 : ₹ 160
Covert 1m to cm : 1m =
So, 25 : 100 =
For, 40 : 160 =
Since, both ratios simplify to
Middle terms :
(b) 39 litres : 65 litres and 6 bottles : 10 bottles
So, 39 : 65 =
For, 6 : 10 =
Since, both ratios simplify to
Middle terms :
(c) 2 kg : 80 kg and 25 g : 625 g
So, 2 : 80 =
For, 25 : 625 =
Since, both ratios simplify to
(d) 200 mL : 2.5 litre and ₹ 4 : ₹ 50
Convert 2.5 liters to ml : 2.5 liters =
So, 200 : 2500 =
For, 4 : 50 =
Since, both ratios simplify to
Middle terms :