The diamond is a square.

Let $\"\"$ be the side of the diamond.

From the figure we observe the distance between home plate and second base is

diagonal of the square.

Find the diagonal by using the Pythagoras theorem:

Diagonal $\"\"$

$\"\"$ ft

Diagonal $\"\"$

$\"\"$

$\"\"$ .

The distance from home plate to second base is $\"\"$ ft.