Math Help - [SOLVED] Related Rates

1. [SOLVED] Related Rates

Hi i have a couple of questions, steps would be nice, thank you!

1) The altitude of a triangle is increasing at a rate of centimeters/minute while the area of the triangle is increasing at a rate of square centimeters/minute. At what rate is the base of the triangle changing when the altitude is centimeters and the area is square centimeters?

2)The demand for apples is given by the equation , where is the number of pounds demanded and is the price per pound. If the price is increasing at a rate of 1.25 dollars per week, when the demand is 10 pounds, at what rate is the
(a) demand changing;
(b) revenue changing.

3) A particle is moving along the curve . As the particle passes through the point , its -coordinate increases at a rate of units per second. Find the rate of change of the distance from the particle to the origin at this instant.

2. Where are you stuck?

For instance, for the first exercise, you've drawn the triangle, labelled the base and the height with "b" and "h", noted that dh/dt = 3 and dA/dt = 2.5, differentiated the formula for the area A of a triangle with height h and base b with respect to time, plugged in the given values, and... then what?

Please be complete. Thank you!

3. I just need someone to do the steps, then i will study the process. I'm not sure how to set up these word problems.

okay, just need help on the last one, can someone help?

4. What is the distance from the origin to the point (x,y)?