Let the larger number be ‘X’, so the smaller number will be ‘Y’.
∴ X2 – Y2 = 45 ––––– (i)
∵4X = Y2 –––––– (ii)
On simplifying further,
Putting the value of Y2 = 4X from equation –––––– (ii)
X2 – 4X = 45
X2 – 4X – 45 = 0
On applying Sreedhracharya formula

X = – 5 or 9
∴ X = 9 (Only natural number, as given in the question)
∴ Y=√(4 x 9)
∴ Y = 6
∴ The numbers are 9 & 6.