A stone is dropped into a lake, causing waves whose radii increase at a rate of 30cm/sec. a) At what rate is the area enclosed by a circular wave increasing when the radius is 50 cm? B) at what rate is the circumference of a circular wave increasing when the radius is 50cm?

150.6

all i did was i multiplied 5.02 by 30

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15

thats one

step-by-step explanation:

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