Problem: Which one of the following combinations of given parts does not determine the indicated triangle?
Answer Choices:
A. base angle and vertex angle; isosceles triangle
B. vertex angle and the base; isosceles triangle
C. the radius of the circumscribed circle; equilateral triangle
D. one arm and the radius of the inscribed circle; right triangle
E. two angles and a side opposite one of them; scalene triangle
Solution:
Combination (A) determines the shape of the triangle, but not its size. All the other combinations determine both the size and the shape of the triangle.