Find the fourth proportional to:(i) 1.5, 4.5 and 3.5 (ii) 3a, 6a2 and

1.	Find the fourth proportional to:(i) 1.5, 4.5 and 3.5 (ii) 3a, 6a2 and 2ab2
Answer» (i) Let the fourth proportional to 1.5, 4.5 and 3.5 be x. ⟹1.5 : 4.5 = 3.5 : x ⟹ 1.5 × x = 3.5 × 4.5 ⟹ x = 10.5 (i) Let the fourth proportional to 3a, 6a² and 2ab² be x. ⟹ 3a : 6a² = 2ab² : x ⟹ 3a × x = 2ab² × 6a² ⟹ 3a × x = 12a³b² ⟹ x = 4a²b²

Find the fourth proportional to:(i) 1.5, 4.5 and 3.5 (ii) 3a, 6a2 and 2ab2

Answer»

(i) Let the fourth proportional to 1.5, 4.5 and 3.5 be x.

⟹1.5 : 4.5 = 3.5 : x

⟹ 1.5 × x = 3.5 × 4.5

⟹ x = 10.5

(i) Let the fourth proportional to 3a, 6a² and 2ab² be x.

⟹ 3a : 6a² = 2ab² : x

⟹ 3a × x = 2ab² × 6a²

⟹ 3a × x = 12a³b²

⟹ x = 4a²b²