Related Rates: A plane, 40 mi from airport, is flying at

[bbsa3412]

Need some help setting up the following problem:

A plane is 40 miles (horizontally away from an airport) flying at a constant altitude of 4 miles. The radar at the airport determines that the distance from the plane to the radar dish is changing at 240 mph. Determine the speed of the plane.

[nona.m.nona]

Start with the triangle: the height line at the airport, labelled with "y = 4"; the horizontal line for the flight path, labelled with "x = 40"; and the hypotenuse, labelled with dD/dt = 240. You are given that dy/dt = 0, and the Pythagorean Theorem gives you that x² + y² = D².

Differentiate implicitly with respect to time, and then plug in the known values. Solve for dx/dt.

[bbsa3412]

Thank you, this helped greatly.