I agree. This is certainly missing and a little frustrating, considering it is a standard grade nine math skill. As well, Khan Academy offers no complex problems that involve finding the slant height of a pyramid from the pyramid height and base length in order to calculate surface area. From what I can see, there needs to be surface area and volume problems for cones, cylinders, pyramids; and using Pythagorean theorem to get measurements needed to calculate surface area or volume for pyramids and cones.

Thanks for your comment Vee. Please vote the thread up so we can get some more interest in this! 

I would like courses  in this subject as well . Something in standard 8 th grade canadian math