**5 Types of Triangles & Parts of Triangles**

Acute Triangle & Obtuse Triangle

A acute triangle is where all angles measure less than a right angle or 90 degrees.

An obtuse triangle is a triangle that has an angle more than 90 degrees.

Isosceles Triangle & Equilateral Triangle

Right Triangle & Scalene Triangles

Median of a Triangle

Median of a Triangle is a line segment joining a vertex of the triangle to the midpoint of the opposite side of the triangle. The three medians of a triangle are concurrent and the concurrent point is called the centroid of the triangle.

("Median of a Triangle," n.d.)

A isosceles triangle is any triangle that has two sides that are the same length.

A equilateral triangle is a triangle where all three sides are the same length.

Altitude of a Triangle

Formally, the shortest line segment between a vertex of a triangle and the (possibly extended) opposite side. Altitude also refers to the length of this segment.

Bisector of a Triangle

Activity

Exit Ticket

References

The definition of the perpendicular bisector of a side of a triangle is a line segment that is both perpendicular to a side of a triangle and passes through its midpoint.

Identify the median of the triangle.

Choices:

A. AD

B. AC

C. CB

D. BD

Draw an example of altitude, median, and bisector of a triangle.

(Gibilisco, 2003)

(Copyright Math Open Reference, n.d.)

("The Altitudes of a Triangle," 2011)

("Constructing the Angle Bisectors of a Triangle," 2011)

("Types of Triangles," n.d.)

**By: Maryann Lyons**

The Altitudes of a Triangle. (2011, May 02). Retrieved May 12, 2014, from

Bruce Simmons. (n.d.). Mathwords: Altitude. Retrieved May 09, 2014, from http://www.mathwords.com/a/altitude.htm

Constructing the Angle Bisectors of a Triangle. (2011, May 02). Retrieved May 5, 2014, from

Copyright Math Open Reference. (n.d.). Isosceles triangle - math word definition - Math Open Reference. Retrieved May 08, 2014, from http://www.mathopenref.com/isosceles.html

Finding The Altitude Of A Triangle. (n.d.). Retrieved May 08, 2014, from http://needmathhelp.jimdo.com/geometry/finding-the-altitude-of-a-triangle

Gibilisco, S. (2003). Geometry demystified. New York: McGraw-Hill.

MathsIsFun.com. (n.d.). Obtuse Triangle. Retrieved May 07, 2014, from http://www.mathsisfun.com/definitions/obtuse-triangle.html

Median of a Triangle - MathHelp.com - Geometry Help. (2007, October 31). Retrieved May 5, 2014, from

Median of a Triangle. (n.d.). Retrieved from https://www.youtube.com/results?search_query=median+of+triangles

Median of a triangle. (n.d.). Retrieved May 09, 2014, from http://www.icoachmath.com/math_dictionary/median_of_a_triangle.html

The Perpendicular Bisectors of a Triangle. (n.d.). Retrieved May 09, 2014, from http://www.geom.uiuc.edu/~demo5337/Group2/perpbisect.html

Triangle Angle Bisector Theorem - MathHelp.com - Math Help. (2008, May 13). Retrieved May 12, 2014, from

Types of Triangles. (n.d.). Retrieved May 08, 2014, from http://www.mathwarehouse.com/geometry/triangles/triangle-types.php

Trigonometry-is a branch of mathematics that studies relationships involving lengths and angles of triangles.

http://en.wikipedia.org/wiki/Trigonometry