Less than 90°
Two angles on the same plane
Two points on the same line
Two angles whose sum is 90°
The point halfway between the endpoints of a segment.
More than 180°
A point on a line and all points in one direction
Two nonadjacent angles formed by two intersecting lines
Adjacent angles whose non-common sides are opposite rays
At least two sides are congruent
Nothing is congruent
Every side is the same length
A and B are bi conditionally related if A implies B and B implies A.
a number which disproves a proposition For example, the prime number 2 is a counterexample to the statement "All prime numbers are odd."
A isometry is a transformation where distance (aka size) is preserved.
Produced by reflection from a mirror, refraction by a lens, or the passage of luminous rays through a small aperture and their reception on a surface.
A transformation in which a graph or geometric figure is picked up and moved to another location without any change in size or orientation.