(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A balloon is rising at a constant speed of 5 ft/s. A boy is cycling along a straight road at a speed of 15 ft/s. When he passes under the balloon, it is 45 ft above him. How fast is the distance between the boy and the balloon increasing 3 seconds later.

2. Relevant equations

dx/dt=15 ft/s

dy/dt=5 ft/s

c^{2}=x^{2}+y^{2}

3. The attempt at a solution

2c dc/dt = 2x dx/dt + 2y dy/dt

c(dc/dt) = x(dx/dt) + y(dy/dt)

c(dc/dt) = x(15) + y(5)

c(dc/dt) = 15x + 5y

My first problem is: Is the 45ft x or y?

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# Homework Help: Related Rates Problem

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