Geometry 4/9/12 homework In chapter ten I have learned many things. A diameter show the length of the circle and divides it into two Semi-circles. A radius is half of the diameter. The circumference of a circle is the distance around the circle.An inscribed angle is and angle that has three points on a circle. A chord is a segment with two points on a circle that doesn't go through the center of the circle. Weather men is this in their forecasting because rainbows have to do with circles and secants. I don't have any problems or questions about this subject.