Question

Find the mean proportional between:
(i) 3 and 27
(ii) 0.9 and 2.5

Answer 1

(i) 3 and 27
Here the mean proportional between them
= $\sqrt{(3\times 27)}$
By multiplication
= $\sqrt{81}$
= 9

(ii) 0.9 and 2.5
Here the mean proportional between them
= $\sqrt{(0.9\times 2.5)}$
Multiplying and dividing by 10
= $\sqrt{(9/10\times 25/10)}$
So we get
= $\sqrt{225/100}$
= 15/10
= 1.5