SnapPad surface area calculationsUpdated a year ago

Curious as to how we calculated the increase in surface area? It’s a snap! Check out this article to see the calculations.

First, most landing feet have a 2” diameter bolt hole (or indent) that doesn’t contact the ground. This is the same diameter as the bolt access hole on all RV SnapPad pads.

The formula to calculate the area of a circle is A = π r² where A is the area of the circle and r is the radius of the circle. A 2” circle, with a 1” radius, therefore has a surface area of 3.14 in².  

Calculating the surface area of an octagon is a little trickier. The formula is A = 2 * a² * (1 + √2) where a = e / (1 + √2) (e is the measurement we use for the diameter). (Hint: a much easier solution is to look up a surface area calculator online).

So, for example for our XTRA pad, e (the diameter) is 11”, so a = 11 / (1 +  √2) or a = 4.556”
Solving for the surface area of the pad is then A = 2 * 4.556² * (1 + √2) or A = 100.224 in².

We then need to subtract the area that the 2” bolt access hole removes from the pad (3.14 in²) leaving us with 97.1 in² (if we round to one decimal).

Next, we need to calculate the surface area of the original jack foot. In our XTRA example the 11” SnapPad fits on 9” round jack feet, but remember the jack feet also have that 2” diameter bolt hole (or indent) that doesn’t contact the ground. With a radius of 4.5” the surface area would be 63.62 in², minus 3.14 in², for a total surface area of 60.5 in² (if we round to one decimal).

Finally, we need to calculate the percent increase in surface area that the SnapPad provides. To do this we first need to find out how much bigger the area of the SnapPad is compared to the area of the jack foot to find the increase. In this example it’s 97.1 - 60.5 = 36.6 in².

We then need to divide that number by the original landing foot size and multiply by 100 to get the percent increase. So in our XTRA example we take 36.6 / 60.5 = 0.605 * 100 = 60.5%. For the purpose of simplicity we rounded up to 61%.

So there you have it! If you have any questions for us feel free to contact us through our website.