Perimeter Calculator
Calculate perimeter for various geometric shapes.
Table of Contents
How to Use
- Select the shape you want to calculate the perimeter for.
- Choose your preferred unit of measurement.
- Enter the required dimensions for your selected shape.
- Click Calculate to see the perimeter and formula used.
What Is Perimeter?
Perimeter is the total distance around the outside of a two-dimensional shape. It's calculated by adding up the lengths of all the sides. For circles, this measurement is called circumference.
Understanding perimeter is essential for many practical applications, from fencing a yard to framing a picture or calculating the border length of any flat surface.
Perimeter Formulas
| Shape | Formula | Variables |
|---|---|---|
| Rectangle | P = 2(l + w) | l = length, w = width |
| Square | P = 4s | s = side length |
| Circle | C = 2πr | r = radius |
| Triangle | P = a + b + c | a, b, c = side lengths |
Real-World Applications
- Fencing: Calculate how much fencing material you need for a yard
- Framing: Determine the frame length needed for pictures or mirrors
- Construction: Measure baseboards, trim, or edging requirements
- Landscaping: Plan borders for gardens, paths, or patios
- Sports: Mark boundaries for fields, courts, or tracks
Frequently Asked Questions
- What's the difference between perimeter and area?
- Perimeter measures the distance around a shape (one-dimensional, in linear units like meters). Area measures the space inside a shape (two-dimensional, in square units like square meters). They use different formulas and serve different purposes.
- Why is circle perimeter called circumference?
- Circumference is the specific term for the perimeter of a circle. The word comes from Latin meaning 'to carry around.' While technically a perimeter, using 'circumference' distinguishes circular measurements from polygons.
- How do I find the perimeter of an irregular shape?
- For irregular shapes, measure each side individually and add them together. If the shape has curved sections, you may need to approximate or use calculus for precise measurements.
- Can two shapes have the same perimeter but different areas?
- Yes! For example, a 1×5 rectangle and a 2×4 rectangle both have a perimeter of 12 units, but their areas are 5 and 8 square units respectively. This principle is important in optimization problems.