1) each side of a square is increasing at a rate of 6cm/s. At what rate is the area of the square is 16 cm^2?

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2)the radius of a sphere is increasing at a rate of 4mm/s.How fast is the volume increasing when the diameter is 80mm?
3)A particle moves along the curve y= (1+x^3)^1/2.As it reaches the point (2,3), the y-coordinate is increasing at a rate of 4 cm/s.How fast is the x-coordinate of the point changing at that instant?