how to figure out perimeter
Instructions. Determine the perimeter of a triangle or rectangle by knowing the length of all of the sides of the figure and then adding these numbers together. The perimeter is the sum of all sides of a figure to get one length. So, to find the perimeter, the formula is base + height + base + height.If the base is 10 inches and the height is 5 inches, you would have: Perimeter: 10 + 5 + 10 + 5 = 30 inches. Determine the area of a rectangle by using multiplication.o, to find the perimeter, the formula is base + height + base + height. If the base is 10 inches and the height is 5 inches, you would have: Perimeter: 10 + 5 + 10 + 5 = 30 inches. Determine the area of a rectangle by using multiplication.