Given in the question:
I = $272.25
r = r = 2.2%
t = 3 years
Let's re-equate the formula of Simple Interest to find P in terms of I, r, and t.
[tex]I\text{ = Prt }\rightarrow\text{ P = }\frac{I}{rt}[/tex]Let's plug in the values to find P.
[tex]P\text{ = }\frac{I}{rt}[/tex][tex]P\text{ = }\frac{272.25}{(\frac{2.2}{100})(3)}\text{ = }\frac{272.25}{(0.022)(3)}[/tex][tex]P\text{ = }\frac{272.25}{0.066}[/tex][tex]P\text{ = 4,125 = \$4,125}[/tex]Therefore, the Principal Amount is $4,125.