O is the centre of the circle with radius 5cm. OPQR is a rectangle. Then PR is

Given radius $=5\text{cm}$

$OB=OA=OQ=$Radius

$\therefore OQ=5\text{cm}$

Also given

$OPQR$ is a rectangle

In rectangle diagonals are equal

$PR=OQ$

$PR=5\text{cm}$