What term describes the length of a straight line passing through the center of a circle and connecting two points on the circumference?

• A. Diameter
• B. Circumference
• C. Radius
• D. Perimeter

Answer: (A)

The diameter is the length of a straight line that passes through the center of a circle and connects two points on the circumference. This line runs from one edge of the circle to the opposite edge, crossing the center, and represents the longest distance across the circle. It’s twice the radius, since the radius goes from the center to the edge and the diameter spans both directions. A radius is just from the center to the circumference, not through the center. The circumference or perimeter describes the boundary length around the circle, not an internal line. So a straight line through the center that connects two points on the circle’s edge is the diameter.