• Aug 27th 2013, 11:13 PM
infoweb
Hi there,

Wondering if someone could help me out with formula to calculate 2 sides length of a 5 sided shape?

For the attached image I have the following dimensions:

A, B and C are all 700 mm

I need to calculate D and E where D = E

Would really appreciate it if someone could either provide a formula or explain how to structure the formula.

Mark
• Aug 28th 2013, 01:56 AM
emakarov
The side of a square with diagonal d (here d = 700) is $\displaystyle \frac{d\sqrt{2}}{2}$.
• Aug 28th 2013, 10:24 AM
bjhopper
Hi infoweb,
If you mean that A+B+C = 700mm there is no unique solution.There is no formula but you can calculate d by assuming A =a fraction of A and C another fraction of d.Express the total of the three sides in terms of d.Equate to 700mm
• Aug 28th 2013, 02:24 PM
infoweb
Hi there,

Thanks for the quick responses. It's been over 20 years since I've done any math like this so I'm totally out of touch!

@Bjhopper

Sorry, I didn't make my self clear enough:

A= 700
B= 700
C= 700

I now need to work out the length of E and D which should be equal to each other.

I tried the formula that emakarov provided but the answer I got didn't seem correct (494.97) not sure if that relates to the length of E and D as it seems too short.

Mark.
• Aug 28th 2013, 02:39 PM
emakarov
$\displaystyle B\sqrt{2}/2$ gives you the side of the square whose diagonal is B. Thus, $\displaystyle D=A+B\sqrt{2}/2$.