Question

calculate the 3rd proportional to 15 and 30

Answer 1

Hi ,

Third proportion:
_____________

If ' x ' is third proportional of ' a ' and ' b'.

Then ,
a : b = b : x

Therefore ,

x = b ^2 / a --------(1)

According to the given problem,

a = 15 , b = 30 ;

Let third proportional = x

Using equation (1)

x = ( 30 )^2 / 15

x = ( 30 × 30 ) / 15

x = 2 × 30

x = 60

Required third proportional = x = 60