The three-dimensional figure shown is a right rectangular prism. What is the area of triangle PQR? Express your answer in simplest radical form.
PR =sqrt (3^2 + 4^2) = sqrt (25) = 5
PQ = sqrt (3^2 + 5^2) = sqrt (34)
OR = sqrt (4^2 + 5^2) = sqrt (41)
Semiperimeter = (5 + sqrt (34) + sqrt (41) ) / 2
[ PQR ] = sqrt ( S ( S - 5) ( S - sqrt 34 ) ( S -sqrt 41 ) ) = sqrt (769) / 2
