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Centroid

The centroid is the geometric centerโ€”the balance point of a shape. Triangle: average of 3 vertices. Rectangle: (L/2, W/2). For uniform density, centroid = center of mass.

Concept Fundamentals
C = ((xโ‚+xโ‚‚+xโ‚ƒ)/3, (yโ‚+yโ‚‚+yโ‚ƒ)/3)
Triangle
C = (L/2, W/2)
Rectangle
C = (ฮฃx/n, ฮฃy/n)
Polygon
Center of mass
Balance

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Triangle centroid lies at intersection of mediansโ€”2/3 from vertex to opposite side. For uniform density, centroid = center of mass. L-shapes and T-sections use composite centroid formulas.

Key quantities
C = ((xโ‚+xโ‚‚+xโ‚ƒ)/3, (yโ‚+yโ‚‚+yโ‚ƒ)/3)
Triangle
Key relation
C = (L/2, W/2)
Rectangle
Key relation
C = (ฮฃx/n, ฮฃy/n)
Polygon
Key relation
Center of mass
Balance
Key relation

Ready to run the numbers?

Why: Centroids are used in structural engineering (load center), physics (center of mass), and design (balance point). Medians of a triangle intersect at centroid.

How: Triangle: centroid = (xโ‚+xโ‚‚+xโ‚ƒ)/3, (yโ‚+yโ‚‚+yโ‚ƒ)/3. Rectangle: (L/2, W/2). Polygon: average of vertices. Composite: weighted area average.

Triangle centroid lies at intersection of mediansโ€”2/3 from vertex to opposite side.For uniform density, centroid = center of mass.

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Centroid CalculatorEnter triangle vertices, rectangle dimensions, or polygon vertices
๐Ÿ“
GEOMETRY2D Centroids

Centroid โ€” Geometric Center

Find centroid of triangles (3 vertices), rectangles (lengthร—width), or composite shapes (polygon vertices).

๐Ÿ“ Real-World Examples โ€” Click to Load

Calculation Settings

For educational and informational purposes only. Verify with a qualified professional.

๐Ÿงฎ Fascinating Math Facts

โ€ข

Centroid = geometric centerโ€”balance point of a shape.

โ€” Definition

โ–ณ

Triangle medians intersect at the centroid.

โ€” Property

๐Ÿ“‹ Key Takeaways

  • โ€ข The centroid is the geometric center โ€” balance point of a shape
  • โ€ข Triangle: centroid = average of 3 vertices; lies at intersection of medians
  • โ€ข Rectangle: centroid = (L/2, W/2) โ€” center of the rectangle
  • โ€ข Composite: for polygons, centroid = average of vertex coordinates
  • โ€ข For uniform density, centroid = center of mass

๐Ÿ’ก Did You Know?

๐Ÿ“Triangle centroid divides each median in 2:1 ratio (closer to vertex)Source: Geometry
๐Ÿ—๏ธEngineers use centroids for beam bending โ€” neutral axis passes through centroidSource: Structural Eng
๐ŸŽฏCenter of a target is the centroid of the circular regionSource: Sports
๐Ÿช‘A chair balances when its center of mass (centroid) is over the baseSource: Physics
๐Ÿ“L-shapes and T-sections have centroids that can lie outside the shapeSource: Engineering
๐Ÿ”ทFor composite shapes, decompose into simple shapes and use weighted averageSource: Mechanics

๐Ÿ“– Formulas Explained

Triangle Centroid

Average of the three vertices. Also the intersection of medians.

C=(x1+x2+x33,y1+y2+y33)C = \left(\frac{x_1+x_2+x_3}{3}, \frac{y_1+y_2+y_3}{3}\right)

Rectangle Centroid

Center of the rectangle โ€” midpoint of the diagonal.

C=(L2,W2)C = \left(\frac{L}{2}, \frac{W}{2}\right)

Polygon Centroid

Arithmetic mean of all vertices for simple polygons.

C=(โˆ‘xin,โˆ‘yin)C = \left(\frac{\sum x_i}{n}, \frac{\sum y_i}{n}\right)

๐ŸŽฏ Expert Tips

๐Ÿ’ก Vertex Order

For polygons, enter vertices in order (clockwise or counter-clockwise).

๐Ÿ’ก L-Shape

Decompose into rectangles: centroid = weighted average by area.

๐Ÿ’ก Right Triangle

Centroid of right triangle (0,0),(a,0),(0,b) is (a/3, b/3).

๐Ÿ’ก Symmetry

If a shape has a line of symmetry, the centroid lies on it.

โš–๏ธ Comparison Table

FeatureThis CalculatorBasicManual
Triangle, rectangle, compositeโœ…โš ๏ธ LimitedโŒ
Step-by-step solutionsโœ…โŒโœ…
Charts & visualizationโœ…โŒโŒ
Copy & shareโœ…โŒโŒ
7 examplesโœ…โŒโŒ

๐Ÿ“Š Quick Facts

3
Triangle Vertices
2
Rectangle Params
nโ‰ฅ3
Polygon Vertices
2:1
Median Ratio

โ“ FAQ

Centroid vs center of mass?

For uniform density they coincide. Center of mass depends on density distribution.

Can centroid be outside the shape?

Yes โ€” for L-shapes, crescents, and other concave shapes.

Does vertex order matter for polygons?

For the arithmetic mean formula, no. For signed-area formula, yes.

How to find centroid of L-shape?

Decompose into rectangles, find each centroid and area, then weighted average.

What is the median ratio in triangles?

Centroid divides each median so the vertex-side segment is 2/3 of the median.

Rectangle with corners (0,0) and (L,W)?

Centroid is (L/2, W/2).

How many points for composite?

At least 3 vertices. Add points in order around the shape.

Units for coordinates?

Use consistent units (m, cm, etc.). Result is in the same units.

โš ๏ธ Disclaimer: Polygon centroid uses arithmetic mean of vertices. For area-weighted centroid of complex shapes, use decomposition.

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