Assessment and Learning in Knowledge Spaces (ALEKS) Practice Exam

How is the diameter of a circle defined?

1. The line segment connecting two points on the circle

2. The distance across the circle through the center

3. The space contained within the circle

4. The arc that bounds the center of the circle

The correct answer is: The distance across the circle through the center

The diameter of a circle is defined as the distance across the circle that passes through the center. This definition is essential in understanding the properties and calculations related to circles. The diameter is essentially the longest chord of the circle, connecting two points on the circle's circumference and bisecting the circle at its center. Knowing the diameter allows you to calculate the radius (which is half of the diameter) and is critical for determining the area and circumference of the circle. In contrast, while connecting two points on the edge of the circle forms a line segment, it does not necessarily pass through the center, thus not defining the diameter accurately. The space contained within the circle refers to its area, not its diameter, and the term "arc" typically pertains to a portion of the circumference rather than the straight-line measure that the diameter represents. Therefore, the clarity in the definition provided helps solidify the foundational concepts of circle geometry.