Geometry · 7 min read

How to Find the Centroid of a Right Triangle at (b/3, h/3)

Right angle at the origin: the three-vertex average collapses to G = (b/3, h/3)

With the right angle at the origin and legs along the axes, the centroid of a right triangle is G = (b/3, h/3) — not a second kind of centroid, just the three-vertex average after two coordinates become zero. This guide derives that origin formula, works b = 6 and h = 4 to G = (2, 4/3), and includes a playground. For any three vertices (right triangle or not), use the Centroid of a Triangle Calculator.

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G = (b/3, h/3) is measured from the right-angle vertex when that vertex sits at the origin. Move the right angle somewhere else and those two numbers are no longer the absolute coordinates of G. The calculator still averages whatever three vertices you type.

1.What G = (b/3, h/3) assumes

The centroid G is where the three medians meet, and it is also the average of the vertices. For a uniform triangular plate it is the balance point. The formula G = (b/3, h/3) is the same average after you park the right angle at (0, 0) and run the legs along the axes. That is a coordinate-frame choice, not a different definition of the centroid.

2.Place the right angle at the origin

Call the legs b (along the x-axis) and h (along the y-axis). The vertices are then A = (0, 0) at the right angle, B = (b, 0), and C = (0, h). That is a choice of axes, not a claim that every right triangle in a textbook drawing already lives there. If your sketch has the right angle in a corner of the page, you may relabel that corner as the origin before you compute. Measuring from the right-angle vertex means those (b/3, h/3) offsets start at A.

3.Why the three-vertex average becomes (b/3, h/3)

Any triangle’s centroid is G = ((x₁+x₂+x₃)/3, (y₁+y₂+y₃)/3). Plug in A, B, and C: the x-coordinates are 0, b, and 0, so Gₓ = (0 + b + 0)/3 = b/3. The y-coordinates are 0, 0, and h, so Gᵧ = (0 + 0 + h)/3 = h/3. From the right-angle vertex, G = (b/3, h/3). You did not need the hypotenuse, an angle, or a median construction — the zero coordinates ate two of the three terms. The same average works for every triangle once you type its three vertices.

\[ G=\left(\frac{b}{3},\frac{h}{3}\right) \]

4.Worked example at the origin: legs 6 and 4

Take b = 6 and h = 4, so the vertices are (0, 0), (6, 0), and (0, 4). Then G = (6/3, 4/3) = (2, 4/3) ≈ (2, 1.33). From the right angle you move 2 units along the base and 4/3 up. The midpoint of the hypotenuse is (3, 2); two-thirds of the way from A toward that midpoint is (2, 4/3), the same G — the 2:1 median check.

\[ G=\left(\frac{6}{3},\frac{4}{3}\right)=\left(2,\tfrac{4}{3}\right) \]

Right triangle with right angle at A(0, 0), B(6, 0), and C(0, 4). Dashed medians meet at centroid G(2, 4/3) = (b/3, h/3) on a cream Cartesian plane.
Right angle at the origin, b = 6, h = 4: G = (b/3, h/3) = (2, 4/3) from A.

5.Legs playground

Move b and h. The sketch keeps the right angle at the origin, draws the medians, and marks G = (b/3, h/3). Under the hood that point is still the average of (0, 0), (b, 0), and (0, h) — the same three-vertex formula. This is a teaching widget, not the full calculator chrome.

Inline playground

G x = b/3

2.00

G y = h/3

1.33

G = (6/3, 4/3) = (2.00, 1.33)

Right triangle at the origin with centroid G = (b/3, h/3) Right angle at (0, 0), legs b and h along the axes, dashed medians meeting at G = (b/3, h/3).
Right angle at the origin. G is the average of (0, 0), (b, 0), and (0, h), which is (b/3, h/3).

Teaching aid only — b and h must be positive legs, with the right angle at (0, 0).

Open the full Centroid of a Triangle Calculator →

6.The shortcut is still the three-vertex formula

Nothing here is a second centroid. The calculator’s default vertices A(0, 0), B(6, 0), C(2, 4) are not a right triangle at the origin, and G is (8/3, 4/3) because that is the average, not because of b/3. When you do have a right angle at (0, 0), the zeros simply make the average look like (b/3, h/3). If the right angle is not at the origin, do not paste (b/3, h/3) onto the page as absolute coordinates — average the three vertices you actually have, or translate so the right angle sits at the origin first.

Triangle ABC with vertices A(0, 0), B(6, 0), and C(2, 4). Dashed medians meet at centroid G(8/3, 4/3) on a cream Cartesian plane.
Same averaging rule, not a right-triangle shortcut: defaults A(0, 0), B(6, 0), C(2, 4) give G = (8/3, 4/3).

7.Open the Centroid of a Triangle Calculator

The Centroid of a Triangle Calculator averages any three vertices and draws the medians. To match this tutorial’s example, type A = (0, 0), B = (6, 0), and C = (0, 4) for G = (2, 4/3). Leave C at (2, 4) if you want the page defaults instead — that is a general triangle, not this right-triangle shortcut. How it works keeps Gₓ and Gᵧ on separate lines plus the 2:1 split along each median.

8.More right-triangle centroid guides

This page is the origin formula G = (b/3, h/3). The same cluster answers the jobs that are easy to mix up with it.

Why "from the right-angle vertex" is a frame choice: How to Measure the Centroid from the Right-Angle Vertex. Legs only, no extra coordinates: How to Get Centroid Coordinates of a Right Triangle from Legs b and h. How the shortcut reduces from G = (A+B+C)/3: How the Right-Triangle Centroid Relates to the Three-Vertex Formula.

Axes, medians, and a plotted G: How to Plot the Centroid of a Right Triangle on the Coordinate Plane. When the right angle is not at (0, 0): How to Find the Centroid When the Right Angle Is Not at the Origin. A 2:1 median check of the same G: How to Check a Right-Triangle Centroid with Medians (2:1 Ratio).