3. The length of a rectangle is increasing at a rate of 3 cm=s and its width is increasing at arate of 9 cm=s. When the length is 7 cm and the width is 5 cm, how fast is the area of therectangle increasing?

The area of the rectangle is increasing at 78cm/sec

Step-by-step explanation:

Explanation:-

Given the length of a rectangle is increasing at a rate of 3 cm/s

Given the width of a rectangle is increasing at a rate of 9 cm/s

we know that the area of the rectangle

                         A = l × w  …(l)

Differentiating equation with respective to 't'

Given the length of the rectangle = 7 cm and

The width of the rectangle w = 5 cm

Final answer:-

The area of the rectangle is increasing at 78cm/sec

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step-by-step explanation:

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