Perimeter is the length around a figure. The way to find perimeter is the distance of each side added together (for squares). But in the case of a triangle you would find the length of each side of the triangle/parallelogram (for lines you can just the length of the line, and for non-straight lines such as the vertical lines of a parallelogram where the point that the line is on the x-axis changes, and do the use the distance formula to find those uneven lines). Then add each up, the sides can be found by counting how farm along the y and x axis it traveled then set it up as this equation, x = .
Try to solve for the perimeter of a scalene triangle!
First to solve for the perimeter you will have to find the length of each side. For example side has a rise of -1 and a run of 5, so the equation would be . then you would do the same for the other sides, b and c, which b should equal 5 and c should equal 3.16. Then you would add them all together so 3.16+5+5.1=13.26.