#### Answer

The radius of the original plate is 5 inches.

#### Work Step by Step

Let $a = 1.4~in$ and let $b = 0.2~in$. We can find the radius of the original plate:
$r = \frac{a^2+b^2}{2b}$
$r = \frac{(1.4~in)^2+(0.2~in)^2}{(2)(0.2~in)}$
$r = 5~in$
The radius of the original plate is 5 inches.