On a number line: What does a closed circle mean and what does an open circle mean?
1 answer:
You might be interested in
Answers:
- circle
- center
- radius
- chord
- diameter
- secant
=======================================
Explanations:
- Consider a campfire and people surrounding it to warm up. The fire itself is the center of the circle, and the people around it are points on the circle's edge. Assume that each person is the same distance away from the fire. Refer to the diagram below.
- We always refer to the circle name by the center point. Think of it being like at the center of the universe, or you could think how the sun is at the center of the solar system. While technically the planets orbit in ellipses and not perfect circles, this idea still could be useful to help remember the naming convention.
- If we go back to the example in part 1, the radius is the distance from the campfire to any given person. The radius is half the diameter.
- This is not to be confused with the spelling "cord" which refers to wiring used in electronics, or in fabric fibers. If we connected any two campers with a segment, then we formed a chord. Refer back to part 1 above. Any diameter is a chord, but not the other way around.
- The diameter is a special type of chord that goes through the center. Note the endpoints of the diameter are on the circle's edge.
- A secant line is basically a chord but we've extended both endpoints off infinitely in both directions. A secant cuts the circle at 2 different points. In contrast, a tangent line touches the circle at exactly one point only.
