# Those Handy Maths Formulars

 Forum topic by Grumpy posted 04-13-2008 04:14 AM 6333 views 8 times favorited 27 replies
 Grumpy23836 posts in 3813 days 04-13-2008 04:14 AM Topic tags/keywords: maths problems maths calculations I will start this one off Jocks. Partridge posted a forum topic on a maths problem http://lumberjocks.com/topics/2954Following I thought it would be a good idea to start a forum on maths formulars and calculations for the benefit of all Jocks.Many of us know the 3-4-5 rule for triangles which comes in very handy in woodwork. gator9t9 raised this one.You can construct a triangle of any size in that 3-4-5 proportion and it will be accurate. I will start with the problem of finding the area of an irregular triangle when you know the lengh of the 3 sides but not the angles. Area of TriangleArea = √[s(s-a)(s-b)(s-c)] where s=1/2 the perimeter & a,b&c are the lengths of the 3 sides.Ok Jocks, lets see what else you have stored in the memory cells. -- Grumpy - "Always look on the bright side of life"- Monty Python