MATHS EX 7B
Chapter 7 - Ratio and Proportion (Including Properties and Uses) Exercise Ex. 7(B) Question 1 Find the fourth proportional to: (i) 1.5, 4.5 and 3.5 (ii) 3a, 6a 2 and 2ab 2 Solution 1 (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, 6a 2 and 2ab 2 be x. 3a : 6a 2 = 2ab 2 : x 3a x = 2ab 2 6a 2 3a x = 12a 3 b 2 x = 4a 2 b 2 Question 2 Find the third proportional to: (i) 2 and 4 (ii) a - b and a 2 - b 2 Solution 2 (i) Let the third proportional to 2 and 4 be x. 2 , 4, x are in continued proportion. 2 : 4 = 4 : x (ii) Let the third proportional to a - b and a 2 - b 2 be x. a - b, a 2 - b 2 , x are in continued proportion. a - b : a 2 - b 2...