An isosceles triangle is a triangle with two congruent sides.; ... When the altitude is drawn in an isosceles triangle, two congruent triangles are formed, proven by Hypotenuse-Leg. ... (The congruent legs of the isosceles triangle become the congruent hypotenuses and the altitude becomes a shared leg.)
www.regentsprep.org/regents/math/geometry/GP6/Lisoscele... www.regentsprep.org/regents/math/geometry/GP6/Lisosceles.htm
Theorem/Properties; Sheet for Proofs ... Base Angle Theorem; (Isosceles Triangle) ... Mid-segment Theorem; (also called mid-line)
regentsprep.org/Regents/mathb/1b/theorems.htm regentsprep.org/Regents/mathb/1b/theorems.htm
Isosceles triangle theorem - Wikipedia, the free encyclopedia
Source
In Euclidean geometry, the isosceles triangle theorem states: In medieval times, when geometry was one of the four subjects of the quadrivium, this theorem acquired the name of Pons Asinorum— the "b...
en.wikipedia.org/wiki/Isosceles_triangle_theorem
Triangle - Wikipedia, the free encyclopedia
Source
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A , B , and C is denoted ...
en.wikipedia.org/wiki/Triangle
Theorems and Postulates for proving triangles congruent; Hypotenuse Leg Theorem | Side Side Side | Side Angle Side | Angle Side Angle | Angle Angle Side |isosceles triangle proofs|CPCTC | indirect proof| quiz on all theorems/postulates...
www.mathwarehouse.com/geometry/congruent_triangles/isos... www.mathwarehouse.com/geometry/congruent_triangles/isosceles-triangle-theorems-proofs.php
Remark: Another equivalent condition for $\overline{AD}$ is that it is the perpendicular bisector of $\overline{BC}$ ; however, this fact is usually not included in the statement of the Isosceles Triangle Theorem.
planetmath.org/encyclopedia/IsoscelesTriangleTheorem.ht... planetmath.org/encyclopedia/IsoscelesTriangleTheorem.html
Theorem (Converse of Isosceles Triangle Theorem)   If $\triangle ABC$ is a triangle with $D \in \overline{BC}$ such that any two of the following three statements are true:
planetmath.org/encyclopedia/ConverseOfIsoscelesTriangle... planetmath.org/encyclopedia/ConverseOfIsoscelesTriangleTheorem.html
In the figure, ABD is an isosceles triangle with AB = BD. ... The theorem states that EF = FC. ... Learn more about this Isosceles Triangle Theorem in our Geometry Formula Atlas...
www.saltire.com/applets/advanced_geometry/isosceles_the... www.saltire.com/applets/advanced_geometry/isosceles_theorem_executable/isosceles_theorem.htm
One of Euclid's theorems is that the base angles of an isosceles triangle are congruent (equal). An isosceles triangle is a triangle in which two of the sides are conguent (equal). The base angles are the angles opposite the two congruent sides. ... The converse of this theorem (If two angles of a triangle are congruent,
www.jimloy.com/geometry/iso.htm
The base, leg or altitude of an isosceles triangle can be found if you know the other two. A perpendicular bisector of the base forms an altitude of the triangle as shown on the right. This forms two congruent right triangles that can be solved using Pythagoras' Theorem as shown below.
www.mathopenref.com/isosceles.html www.mathopenref.com/isosceles.html