Finding the equation for a word problem

Hey and thanks for looking

"An airplane is flying at a constant speed and altitude, on a line that will take it direclty over a radar station located on the ground. At the instant that the plane is 600,000 feet from thes tation, an observer in the station notes that its angle of elevation is 30 degree and is increasing at a rate of 0.5 degree per second. Find the speed of the airplane."

First of all, my question is is there an equation that can relate to the word problem which will allow me to find the speed of the plane using the derivative method?

Sorry if I'm not clear enough