FTCE General Knowledge Math Practice Test

What is a triangle?

1. A polygon with four sides

2. A polygon with three sides

3. A shape that cannot contain angles

4. A quadrilateral with right angles

The correct answer is: A polygon with three sides

A triangle is defined as a polygon that has three sides and three angles. The properties that make a shape a triangle include its three vertices, the segments connecting those vertices (the sides), and the angles formed by these sides. This characteristic of having three sides is fundamental to the definition of a triangle, distinguishing it from other polygons such as quadrilaterals, which have four sides. The concept also emphasizes the significance of angles, as every triangle involves internal angles whose measures sum to 180 degrees. The other options do not accurately describe a triangle; a polygon with four sides refers to quadrilaterals, a shape without angles cannot be defined as a polygon, and a quadrilateral with right angles specifically refers to a rectangle or square, which also does not fit the definition of a triangle.