How to find the perimeter of a polygon

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Math › How to find the perimeter of a polygon

Questions 1 - 4
1

Polygon

All segments of the polygon meet at right angles (90 degrees). The length of segment \overline{AB} is 10. The length of segment \overline{BC} is 8. The length of segment \overline{DE} is 3. The length of segment \overline{GH} is 2.

Find the perimeter of the polygon.

\dpi{100} \small 46

\dpi{100} \small 48

\dpi{100} \small 44

\dpi{100} \small 40

\dpi{100} \small 42

Explanation

The perimeter of the polygon is 46. Think of this polygon as a rectangle with two of its corners "flipped" inwards. This "flipping" changes the area of the rectangle, but not its perimeter; therefore, the top and bottom sides of the original rectangle would be 12 units long \dpi{100} \small (10+2=12). The left and right sides would be 11 units long \dpi{100} \small (8+3=11). Adding all four sides, we find that the perimeter of the recangle (and therefore, of this polygon) is 46.

2

What is the perimeter of a regular nonagon with a side length of ?

Explanation

To find the perimeter of a regular polygon, we take the length of each side, , and multiply it by the number of sides, .

In a nonagon the number of sides is , and in this example the side length is .

The perimeter is .

3

Find the perimeter of the following octagon:

20

Explanation

The formula for the perimeter of an octagon is .

Plugging in our values, we get:

4

What is the perimeter of a regular hendecagon with a side length of 32?

Explanation

To find the perimeter of a regular hendecagon you must first know the number of sides in a hendecagon is 11.

When you know the number of sides of a regular polygon to find the perimeter you must multiply the side length by the number of sides.

In this case it is .

The answer for the perimeter is .

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