Find the third proportional to : (i) 36, 12 (ii) 1.2, 0.6 (iii) (iv) 1m 60 cm, 40 cm (v) 1 kg 250 g, 500 g (vi) ₹ 2.40, ₹ 4.80

Question

KnowledgeBoat · Accepted Answer

(i) 36, 12 Let the third proportional be x. Then, 36 : 12 :: 12 : x. product of extremes = product of means 36 × x = 12 × 12 ⇒ x = ⇒ x = 4 Hence, the third proportional is 4 (ii) 1.2, 0.6 Let the third proportional be x. Then, 1.2 : 0.6 :: 0.6 : x. product of extremes = product of means 1.2 × x = 0.6 × 0.6 ⇒ x = ⇒ x = ⇒ x = 0.3 Hence, the third proportional is 0.3 (iii) Let the third proportional be x. Then, . product of extremes = product of means Hence, the third proportional is 4 (iv) 1 m 60 cm, 40 cm First, convert to the same unit: 1 m = 100 cm ∴ 1 m 60 cm = 100 cm + 60 cm = 160 cm. Let the third proportional be x. Then, 160 : 40 :: 40 : x product of extremes = product of means 160 × x = 40 × 40 ⇒ x = ⇒ x = 10 Hence, the third proportional is 10 cm (v) 1 kg 250 g, 500 g First, convert to the same unit: 1 kg = 1000 g ∴ 1 kg 250 g = 1000 g + 250 g = 1250 g Let the third proportional be x. Then, 1250 : 500 :: 500 : x product of extremes = product of means 1250 x x = 500 x 500 ⇒ x = ⇒ x = ⇒ x = 200 Hence, the third proportional is 200 g (vi) ₹ 2.40, ₹ 4.80 Let the third proportional be x. Then, 2.40 : 4.80 :: 4.80 : x. product of extremes = product of means 2.40 × x = 4.80 × 4.80 ⇒ x = ⇒ x = 2 x 4.80 ⇒ x = 9.60 Hence, the third proportional is ₹ 9.60

Mathematics

Find the third proportional to : (i) 36, 12 (ii) 1.2, 0.6 (iii) (iv) 1m 60 cm, 40 cm (v) 1 kg 250 g, 500 g (vi) ₹ 2.40, ₹ 4.80

Ratio Proportion

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