Assessment and Learning in Knowledge Spaces (ALEKS) Practice Exam

What is a radius in terms of a circle?

1. The diameter divided by two

2. A segment from the center to the circle's edge

3. The distance from one edge of the circle to the center

4. A full line that runs through the circle's center

The correct answer is: A segment from the center to the circle's edge

A radius in a circle is defined as a line segment that connects the center of the circle to any point on its circumference. This definition reflects the fundamental geometric property of a circle, emphasizing how the radius is not only a measure of distance but also serves as a key component in calculating various attributes of the circle, such as its area and circumference. Option B accurately captures this concept by stating that a radius is a segment from the center to the edge of the circle. It illustrates the essential relationship between the center of the circle and the boundary, which is crucial for understanding the circle's geometry. The other options, while related to the concept of circles, do not precisely define what a radius is. For instance, dividing the diameter by two would yield the radius but doesn’t directly define it. Similarly, stating that the radius is the distance from the edge of the circle to the center does not capture the segment's nature or directionality, while describing a full line that runs through the center actually describes the diameter, which is a different concept altogether. The focus on the segment from the center to the edge in option B is what makes it the correct interpretation of a radius.