Problem:
Which of the following triangles cannot exist?
Answer Choices:
A. An acute isosceles triangle
B. An isosceles right triangle
C. An obtuse right triangle
D. A scalene right triangle
E. A scalene obtuse triangle
Solution:
A triangle cannot contain one angle and another angle greater than since the three angles must sum to . Triangles with sides having the following lengths show that each of the others is possible: