If A : B = 3 : 4, B : C = 5 : 7 and C : D = 8 : 9, then A : D is:

To find A : D, we need to combine the given ratios: A : B = 3 : 4, B : C = 5 : 7, and C : D = 8 : 9.

Step 1: Make the common term B equal in both A:B and B:C. The LCM of 4 and 5 is 20.

Multiply A : B = 3 : 4 by 5 → A : B = 15 : 20

Multiply B : C = 5 : 7 by 4 → B : C = 20 : 28

Now, A : B : C = 15 : 20 : 28

Step 2: Now combine A : C = 15 : 28 with C : D = 8 : 9.

Make C equal in both ratios. LCM of 28 and 8 is 56.

Multiply A : C = 15 : 28 by 2 → A : C = 30 : 56

Multiply C : D = 8 : 9 by 7 → C : D = 56 : 63

Now, A : C : D = 30 : 56 : 63

Therefore, A : D = 30 : 63, which simplifies to 10 : 21.

हिन्दी उत्तर: A : D का अनुपात 10 : 21 है।