how to calculate?

[argpilot]

an A/C is mantaining a 5.2% gradient and is at 7nm from the runway on a flat terrein, its height is?

can anyone help me with this?
thanks

 

[DC8 Flyer]

climb gradient is simply rise over run. 5.2% equals 5.2 feet UP for every 100 feet FORWARD. So, going with 1 nm = 6000 feet (round numbers):

7NM = 42000 feet, 5.2 feet up for every 100 feet forward (5.2% of 42000) is 2184 feet.

I have a nice .pdf file that talks about aircraft performance if you like, PM your email and I will send it to you.