Question

find x in each of the followig.
1)12:x= x:48
2)12:21::8:x

Q2)find the mean proportional between:

1)12 and 27
2) 5 and 45
3) 4 and 9

Answer 1

I will do the first one:

12:x + x:48
12/x = x/48
cross-multiply
x^2 = 576
x = ± √576
x = ± 24

In the second part , you are doing the same thing
1. let that mean proportional be x
then 12:x = x:27
12/x = x/27
x^2 = 324
x = ± √324
x = ± 18

I will let you try the rest.