# Isosceles Triangle (Properties)

Definition: An ISOSCELES TRIANGLE is a triangle that has AT LEAST 1 PAIR OF CONGRUENT SIDES. Directions: 1) Click on the red checkbox to illustrate this definition. 2) Move any 1 (or more) of the vertices of this triangle around. Does it remain isosceles? 3) Click on checkbox 2. Move the vertices of the triangle around again. What do you notice? 4) Click on checkbox 3. This will draw the line that bisects the vertex angle of the isosceles triangle. 5) Click on checkbox 4. What else do you notice? 6) Please answer the questions that appear below this applet.
Questions: Fill in the following blanks (based upon your observations).  The words to complete these statements can be found in the word bank below.   1) If two sides of a triangle are congruent, then the _____________________ opposite those sides are ____________________. 2) The ___________________ of the _________________ angle of an isosceles triangle is the ________________________ ________________ of the base (3rd side). Word Bank:   bisector   angles     congruent     perpendicular    vertex    bisector