# Geometry CS Mid Year Study Set

## 50 terms

### alternate exterior angles

lie outside the two coplanar lines on opposite sides of a transversal

### alternate interior angles

lie between the pair of coplanar lines and on opposite sides of the transversal

### construction

a geometric drawing made with a compass and a straight edge

### converse

is formed by switching the hypothesis and conclusion of an if-then statement

### corresponding angles

non-adjacent angles that lie on the same side of a transversal, one interior and one exterior to the two coplanar lines

### image

the figure that results from a transformation

### parallel lines

Lines that are in the same plane and never intersect

### parallel planes

two planes that do not intersect

### perpendicular lines

two lines that intersect to form a right angle.

### same-side interior angles

two interior angles which lie on the same side of a transversal

### skew lines

Lines that are neither parallel or intersecting, they lie in two different planes

### transformation

an operation that maps or moves a figure onto an image

### translation

a transformation that slides an object from one point to another the same distance and in the same direction

### transversal

a line that intersects two or more coplanar lines at different points

two angles in the same plane that share a common side, have the same vertex and do not overlap

### bisect

divide a geometric figure into two equal parts

### complementary angles

two angles whose measures have a sum of 90 degrees

### deductive reasoning

using facts, definitions, accepted properties and the laws of logic to make a logical argument

### if-then statement

a statement with two parts: an "if" part that contains an hypothesis, and a "then" part that contains a conclusion

### linear pair

two angles that are adjacent and together form a line

### midpoint

the point that divides a segment into 2 congruent parts

### segment bisector

a line, segment or ray that goes through the midpoint of a segment

### supplementary angles

two angles that have measures whose sum is 180 degrees.

### vertical angles

angles which are formed opposite one another when two lines intersect

### acute angle

an angle whose measure is greater than 0 and less than 90 degrees

### congruent

having the same size and shape

### conjecture

an unproven statement that is based on a pattern or observations

### counterexample

an example that proves a conjecture false

### degrees

the unit used to measure angles

### distance between two points

is the length of the path between two points; is always positive

### inductive reasoning

a process that includes looking for patterns and making conjectures

### line

has one dimension and extends without ends in two opposite directions; is represented by a long,thin, straight mark with arrowheads on either end

### obtuse angle

an angle measuring more than 90 degrees but less than 180 degrees.

### plane

has two dimensions; is represented by a shape that looks like a floor or a wall and extends indefinitely

### point

an exact place or position in space that has no dimension, represented by a small dot .

### ray

a section of a line that begins at one endpoint and extends in one direction from that endpoint

### right angle

an angle that measures 90 degrees.

### segment

part of a line that consists of two points(called endpoints) and all the points on the line that are between the endpoints

### straight angle

an angle whose measure is exactly 180 degrees

### vertex of an angle

the endpoint of an angle where the two sides intersect

### triangle

a three-sided polygon

### equilateral triangle

a triangle with three congruent sides

### isosceles triangle

a triangle with at least two congruent sides

### scalene triangle

a triangle with no congruent sides

### equiangular triangle

A triangle with 3 congruent angles

### acute triangle

A triangle with three acute angles

### right triangle

a triangle with one right angle

### obtuse triangle

a triangle with one obtuse angle

### line of symmetry

a line that divides a figure into two halves that are mirror images of each other

### rotational symmetry

The ability of a figure to be rotated less than a full circle and exactly match its original image