How to Find the Length in Centimeters of a Triangle

A triangle is a three-sided polygon.

The sum of the length of all of the sides of any polygon is called the perimeter. A triangle is a three-sided polygon that can be drawn with varying angles and lengths of its edges. Find the length of a polygon in centimeters by using a metric ruler to measure all of the sides. Metric rulers use centimeters and millimeters instead of inches to determine length. Many rulers have metric and standard units of measurement on each side.

Things You'll Need

• Metric ruler
• Pencil
• Paper

Instructions

1. Draw a triangle. Use a ruler to make your edges straight.

2. Measure the length of one edge of the triangle, using your metric ruler. Write down the length of the first edge in centimeters.

3. Use the ruler again to measure the length of the second edge of your triangle. Take note of the length of the second edge.

4. Determine the length of the third edge of the triangle by measuring it with the ruler. Write down the length of the last edge.

5. Add all of the lengths of the edges together to find the total length of all the edges.

Tips & Warnings

• A similar method can be used for most polygons.

• Draw your triangle with a ruler to avoid irregular lines.

References

• Math Goodies: Perimeter