the area of a rectangular field is equal to 200 square meters . its perimeter is equal to 60 meters . find the width of this rectangle .
"l * w = 200 : area , l is the length and w is the width . 2 l + 2 w = 60 : perimeter l = 30 - w : solve for l ( 30 - w ) * w = 200 : substitute in the area equation w = 10 and l = 20 : correct answer b"
divide(subtract(divide(60, const_2), sqrt(subtract(multiply(divide(60, const_2), divide(60, const_2)), multiply(const_4, 200)))), const_2)