Question 838484
The diameters of 2 circles are in the ratio 3:4 and the sum of their areas is equal to the area of a circle whose diameter measure 30m.
 Find the diameters of the 2 circles. 
:
Their radii will also have a 3:4 ratio
let x = the multiplier
then
3x = the radius on one circle
and
4x = the radius of the other
:
{{{(pi*(3x)^2) + (pi*(4x)^2)}}} = {{{pi*15^2}}}
divide thru by pi
9x^2 + 16x^2 = 225
25x^2 = 225
divide both sides by 25
x^2 = 9
x = 3 is the multiplier
then
3(3) = 9 is the radius of the 1st circle; diameter is 18
and
4(3) = 12 is the radius of the 2nd circle; diameter is 24