The length of a rectangle is increasing at a rate of 6 cm/s and its width is increasing at a rate of 5 cm/s. when the length is 15 cm and the width is 9 cm, how fast is the area of the rectangle increasing?
By definition, the area of a rectangle is given by: A = w * l Where, w: width l: long Deriving this expression we have: A '= w' * l + w * l ' Substituting the values: A '= (5) * (15) + (9) * (6) A '= 129 cm ^ 2 / s Answer: The area of the rectangle is increasing at: A '= 129 cm ^ 2 / s