HG 2
D3. Given two points O and A. The set of all points P such that ( OP is congruent to OA is called a
circle with O as center, and each of the segments OP is called a radius of the circle.
A4. For every point O and every point A (A ¹ O) there exists a circle with center O and radius OA. (Or
"a circle can be drawn with any given center and radius").
D4. The ray AB is the following set of points lying on the line AB: those points
that belong to the segment AB and all points C such that B is between A and C. The ray AB is said
to emanate from A and to be part of line AB.
D5. An angle with vertex A is a point A together with two rays AB and AC (called
sides of the angle) emanating from A.
D6. Rays AB and AC are opposite rays if they are distinct, if they emanate from
the same point A, and if they are part of the same line AB = AC.