Geometry

2. each of the parts into which something is or may be divided.a part of a figure cut off by a line or plane intersecting it.
3. A special right triangle is a right triangle with some regular feature that makes calculations on the triangle easier, or for which simple formulas exist. For example, a right triangle may have angles that form simple relationships, such as 45°–45°–90°
6. refers to a point that is in the middle of the line joining two points. The two reference points are the endpoints of a line
8. a function f from a metric space M into itself that satisfies the identity d=rd for all points x, y
11. two angles whose sum is 90 degrees.
13. next to or adjoining something else. Having a common vertex and a common side.
14. used to refer to an object that is invariant under some transformations; including translation, reflection, rotation or scaling.
15. property if both the sides of an equation are multiplied by the same number, the expressions on the both sides of the equation remain equal to each other.
18. coplanar infinite straight lines that do not intersect at any point.
19. the circular movement of an object around a centre
20. property subtracting the same number from both sides of an equation does not affect the equality.

1. the division of something into two equal or congruent parts.
4. a special point, usually denoted by the letter O, used as a fixed point of reference for the geometry of the surrounding space.
5. if the sum of two angles is 180 degrees
7. a system that uses one or more numbers, or coordinates, to uniquely determine the position of the points or other geometric elements
9. is a point, line, or curve common to two or more objects.
10. arranged in or extending along a straight or nearly straight line.progressing from one stage to another in a single series of steps; sequential.
12. a polygon with three edges and three vertices. It is one of the basic shapes in geometry.
16. an infinitely long object with no width, depth, or curvature.
17. a primitive notion that models an exact location in space, and has no length, width, or thickness.