The approximate “reach” of a playground swing set slide (the horizontal distance along the play surface from the deck to the end of the slide exit), can be determined by using the little high school geometry equation you might remember called the Pythagorean Theorem:
A2 + B2 = C2.A is the deck height and C is the slide length, so solving the equation for B will give you the “reach” of the slide.
Example: A playground slide is 10' long and is going to be attached to a structure deck that is 5' off the play surface, so the calculation looks like this:
52 + X2 = 102... 25 + X2 = 100... so X = the square root of 75 or 8.66 feet.
A simpler way to figure this out is to simply multiply the playground slide’s length by .866.