Orthocenter, centroid, circumcenter, incenter, line of Euler, heights, medians, The orthocenter is the point of intersection of the three heights of a triangle. Every triangle has three “centers” — an incenter, a circumcenter, and an orthocenter — that are Incenters, like centroids, are always inside their triangles. Triangles have amazing properties! Among these is that the angle bisectors, segment perpendicular bisectors, medians and altitudes all meet with the .

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Incenter Draw a line called the “angle bisector ” from a corner so that it splits the angle in half Where all three lines intersect is the center of cehtroid triangle’s “incircle”, called the “incenter”: Inscribed Circle and Angle Bisectors.

You can look at the above example of an acute triangle, or the below examples of an obtuse triangle and a right triangle to see that this is the case. The radius of the circle is obtained by dropping a perpendicular from the incenter to any of the triangle legs. To see that the incenter is in fact always inside the triangle, let’s take a look at an obtuse triangle and a right triangle.

I believe all of these can be proved using vectors and also expressions for finding these points in any triangle can be found. There is an interesting relationship between the centroid, orthocenter, and circumcenter of a triangle.

### Math Forum – Ask Dr. Math

If you have Geometer’s Sketchpad and would like to see the GSP constructions of all four centers, click here to download it. It can be used to generate all of the pictures above. The circumcenter is the point of intersection of the three perpendicular bisectors. Centroid Draw a line called a “median” from a corner to the midpoint of the opposite side.

The centroid divides each median into two segmentsthe segment joining the centroid to the vertex is twice the length of the length of the line segment joining the midpoint to the opposite side. For the centroid in particular, it divides each of the medians in a 2: If you have Geometer’s Sketchpad and would like to see the GSP construction of the orthocenter, click here to download it. Remember, the altitudes of a triangle do not go through the midpoints of the legs unless you have a special triangle, like an equilateral triangle.

The incenter is the last triangle center we will be investigating. A perpendicular bisectors of a triangle is each line drawn perpendicularly from its midpoint.

Orthocenter, Centroid, Circumcenter and Incenter of a Triangle. The circumcenter is the center of the circle such that all three vertices of the circle are the same distance away from the circumcenter.

It is found by finding the midpoint of each leg of the triangle and constructing a line perpendicular to that leg at its midpoint. This page summarizes some of them. This file also has all the centers together in one picture, as well as the equilateral triangle.

Circumcenterconcurrency of the three perpendicular bisectors. Sorry I don’t know how to do diagrams on this site, but what I mean by that is: A median is each of the straight lines that joins the midpoint of a side with the opposite vertex.

### Orthocenter, Centroid, Circumcenter and Incenter of a Triangle

Orthocenter Draw a line called the “altitude” tgiangle right angles to a side and going through the opposite corner. Circumcenterconcurrency of the three perpendicular bisectors Incenterconcurrency of the three angle bisectors Orthocenterconcurrency of the three altitudes Centroidconcurrency of the three medians For any triangle all three medians intersect at one point, known as the centroid.

Thus, the radius of the circle is the distance between the circumcenter and any of the triangle’s three vertices. The centroid is the point of intersection of the three medians. The three altitudes lines perpendicular to one side that pass through the remaining vertex of the triangle intersect at one point, known as the orthocenter of the triangle. Barycentric Coordinateswhich provide a circumcentdr of calculating these triangle centers see each of the triangle center pages for circumcented barycentric coordinates of that center.

You see that even though the circumcenter is outside the triangle in the case of the obtuse triangle, it is still equidistant from all three vertices of trlangle triangle.

## Triangle Centers

The incenter is the center of the circle inscribed in the triangle. Like the centroid, the incenter is always inside the triangle. In the obtuse triangle, the orthocenter falls outside the triangle.

An altitude of the triangle is sometimes called the height. SKIP to Assignment 5: