The perimeter is the total distance around the outer edge of the figure. It's the total amount of fence you need to enclose the region.
So we simply add up all the side lengths. Refer to the diagram to see any missing sides that aren't labeled (shown in blue).
For instance, the perimeter for problem 1 is 5+2+2.5+4+2.5+6 = 22 cm. Problems 2 and 3 are handled the same way.
It's not a typo that the perimeters of problems 1 and 2 are the same value. This is because both figures can be surrounded by a rectangle that is 6 cm across and 5 cm tall. The perimeter of the surrounding rectangle is exactly the same as the perimeter of the inner fenced region. We're effectively just moving fence around but not changing the perimeter.
<span>Well the third and last option are not rational, since all angles are not right angles, and just because they are comp does not mean they are congruent.</span>
when rounding numbers: if it's four or less, you round down. if it's five or more, you round up. 9 is bigger than 4, so the nearest whole number is 830.