In the diagram, two pairs of identical isosceles triangles are cut off of square ABCD, leaving rectangle PQRS. The total area cut off is 200\:m^2. The length of PR, in metres, is

**Answer Choices**

A. \sqrt{200}

B. 20

C. \sqrt{800}

D. 25

E. 15

In the diagram, two pairs of identical isosceles triangles are cut off of square ABCD, leaving rectangle PQRS. The total area cut off is 200\:m^2. The length of PR, in metres, is

**Answer Choices**

A. \sqrt{200}

B. 20

C. \sqrt{800}

D. 25

E. 15