Once kate's kite reaches a height of 50 feet (above her hands), it rises no higher but drifts due east in a wind blowing at the rate of 5 ft/s. how fast is the string running through kate's hands at the moment that she has released 120 ft of string?
which sides are changing? assign variables to them.
which rate is given?
which rate do you have to find?
write an equation connecting the variables.
differentiate.
solve for the unknown rate.