Triangles and Proof

Define a scalene triangle.

No sides are congruent

Define an isosceles triangle.

At least 2 sides are congruent

Define an equilateral triangle.

All 3 sides are congruent

Define an acute triangle.

All angles are acute

Define a right triangle.

1 right angle, 2 acute angles

Define an obtuse triangle.

1 obtuse angle, 2 acute angles

Define the Triangle Sum Theorem.

The sum of the angles in any triangle adds up to 180 degrees.

Define the Exterior Angle Theorem.

The sum of the remote interior angle measures equals the exterior angle measure.