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?

Respuesta :

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