Remember: If the two circles touch externally, then the distance between their centres is equal to the sum of their radii. Let the radii of the given circles be x cm and (14 – x) cm. ∴πx2+π(14−x)2=130π ⇒x2+196+x2−28x=130 ⇒2x2−28x+66=0 ⇒x2−14x+33=0 ⇒(x−11)(x−3)=0 ⇒x=11,3 Thus, the difference in the radii ofthe circles is 8 cm