http://www.ck12.org Chapter 4. Triangles and Congruence
CK-12 Foundation: Chapter4TriangleSumTheoremB
Concept Problem Revisited
The Bermuda Triangle is an acute scalene triangle. The angle measures are in the picture below. Your measured
angles should be within a degree or two of these measures. The angles should add up to 180◦. However, because
your measures are estimates using a protractor, they might not exactly add up.
The angle measures in the picture are the measures from a map (which is flat). Because the earth is curved, in real
life the measures will be slightly different.
Vocabulary
Atriangleis a three sided shape. All triangles have threeinterior angles,which are the inside angles connecting the
sides of the triangle. Thevertexis the point where the sides of a polygon meet. Special types of triangles are listed
below:
Scalene: All three sides are different lengths.
Isosceles: At least two sides are congruent.
Equilateral: All three sides are congruent.
Right: One right angle.
Acute: All three angles are less than 90◦.
Obtuse: One angle is greater than 90◦.
Equiangular: All three angles are congruent.
Guided Practice
- Determinem^6 1 in this triangle: