Chapter 8 - Section 8.1 - The Square Root Property and Completing the Square - Exercise Set - Page 594: 77

$6.25$%

Since, $A=(1+r)^t$ Plug the values in the given expression. Such as $A=(1+r)^t$ or, $1445=1280(1+r)^2$ This implies that $r=\sqrt {\dfrac{1445}{1280}}-1$ or, $r=0.0625$ and Hence, $r$ can be written as: $r = 6.25$%