Question

$P$ is a point interior to rectangle $ABCD$ and such that $PA=3$ inches, $PD=4$ inches, and $PC=5$ inches. Then $PB,$ in inches, equals:

$2\sqrt3$

$3\sqrt2$

$3\sqrt3$

$4\sqrt2$

$2$

Use the rectangle identity $PA^2+PC^2=PB^2+PD^2$

Substitute the three known distances and solve for $PB^2$

For any point in a rectangle, the British flag theorem gives $PA^2+PC^2=PB^2+PD^2.$ Thus $9+25=PB^2+16,$ so $PB^2=18$ and $PB=3\sqrt2.$

Therefore, the correct answer is B.