Think about it...
Is it possible for an equilateral triangle to have an angle measure other than 60°?
Are isosceles triangles always acute triangles?
Name the Triangles you can classify by their...
Sides:
Angles:
Warm Up: Try to draw the following Try-angles
Obtuse Isosceles triangle: | Obtuse Equilateral triangle: | Right Obtuse triangle: |
Right Isosceles triangle: | Right Equilateral triangle: | Right Scalene Triangle: |
5.4 Equilateral Triangles & Isosceles
Reason with isosceles & equilateral triangles.
Draw an Isosceles Triangle!
→ Use a ruler to make sure two side lengths are the same
→ Measure each angle with a protractor
What do you notice??
Isosceles Triangles:
If two sides of a triangle are congruent, then the angles opposite them are congruent.
If AB ≅ AC , then ∠B ≅ ∠C.
If two angles of a triangle are congruent, then the sides opposite them are congruent.
If ∠B ≅ ∠C, then AB ≅ AC .
Can you have an equilateral triangle that is not equiangular??
A triangle is Equilateral if and only if it is Equiangular.
Find all the Angle Measures of the triangle:
In △DEF, DE ≅ DF .
What can you observe from the triangle??
Copy & complete the following statements:
Find x and y.
Warm Up:
Given Fill in the blanks