Find the third proportional to :
(i) 223 and 4
(ii) a - b and a2−b2
(i) Let the third proportional to 83
and 4 be x.
⟹83,4,x are in continued proportion.
⟹ 83:4=4:x
⟹ 834 : 4x
⟹x=16×38=6
(ii) Let the third proportional to a − b and a2−b2
be x.
⟹ a−b,a2−b2 and x are in continued proportion.
⟹a−b:a2−b2=a2−b2:x
⟹(a−b)(a2−b2)=(a2−b2)x
⟹x= (a2−b2)2(a−b)
⟹x=(a+b)(a−b)(a2−b2)(a−b)
⟹x = (a+b)(a2−b2)