This concept has shown up 7 times this year, with a median placement at question # 45.
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Number Dojo Level: 136
It may be helpful for you to review PolygonDiag, which included a discussion about all the prefixes used to identify different polygons. The assumption made in each problem is that each side of the polygon has equal length. These are usually simple calculations, once you have determined how many sides the polygon has.
Example 1: The perimeter of a regular octagon with an edge of 125 is ___
- An octagon has 8 sides.
- To find the perimeter, multiply 8 by 125. The answer is 1000.
Example 2: The perimeter of a regular pentagon with side length 8.6 cm is ___ cm
- A pentagon has 5 sides.
- Multiply 5 x 8.6 to find the perimeter (use Double/Half to simplify this). 5 x 8.6 = 10 x 4.3, which is 43.
Example 3: The perimeter of a dodecagon with side 9 is ___
- A dodecagon has 12 sides.
- 9 x 12 = 108.
Example 4: The perimeter of an undecagon with edge length 24 is ___
- An undecagon has 11 sides.
- 11 x 24 (using Mult11) = 264.
Example 5: If the perimeter of a regular hexagon is 78, then the length of each side is ___
- A hexagon has 6 sides.
- 78 ÷ 6 = 13.