Isosceles Right Triangle
Pronunciation: /aɪˈsɒ.səˌliz raɪt ˈtraɪˌæŋ.gəl/ Explain
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 Manipulative 1  Isosceles Right Triangle Created with GeoGebra. 

An isosceles right triangle is a
triangle
with one
right angle
where the measures of the other two angles are equal. Since the sum of the angles of a
triangle is 180°, the measure of each of the equal
angles is (180°  90°) ÷ 2 = 45°.
Properties of isosceles right triangles
 One angle of an isosceles right triangle is a
right angle.
 The two base angles of an isosceles right triangle are congruent.
 The two base angles of an isosceles right triangle both measure
45° = π/4 radians.
 The two sides of an isosceles right triangle opposite the base angles are
congruent.
 The area of an isosceles right triangle is
where b is the length of one of the legs.
 The perimeter of an isosceles right triangle is
where b is the
length of one of the legs.

References
 McAdams, David E.. All Math Words Dictionary, isosceles right triangle. 2nd Classroom edition 201501084799968. pg 103. Life is a Story Problem LLC. January 8, 2015. Buy the book
 Casey, John, LL.D., F.R.S.. The First Six Books of the Elements of Euclid. pp 8,1923. Translated by Casey, John, LL.D. F.R.S.. www.archive.org. Hodges, Figgis & Co.. 1890. Last Accessed 8/7/2018. http://www.archive.org/stream/firstsixbooksofe00caseuoft#page/8/mode/1up/search/isosceles. Buy the book
 Sterling, Mary Jane. Trigonometry For Dummies. pg 92. For Dummies. January 28, 2005. Last Accessed 8/7/2018. Buy the book
 Maekawa, Jun. Genuine Origami: 43 MathematicallyBased Models. pg 21. Japan Publications Trading, November 1. 2008. Last Accessed 8/7/2018. Buy the book
Cite this article as:
McAdams, David E. Isosceles Right Triangle. 4/23/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/i/isoscelesrighttriangle.html.
Image Credits
Revision History
4/23/2019: Updated equations and expressions to new format. (
McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (
McAdams, David E.)
8/6/2018: Removed broken links, updated license, implemented new markup, implemented new Geogebra protocol. (
McAdams, David E.)
3/3/2010: Added "References", added "Properties of isosceles right triangles". (
McAdams, David E.)
8/13/2008: Changed image to GeoGebra manipulative. (
McAdams, David E.)
7/11/2007: Initial version. (
McAdams, David E.)