Domain Three- Geometry And Measurement Flashcards
Plane geometry
Study of shapes and figures in two dimensions
Solid geometry
Study of shapes and figures in three dimensions
Point
Most fundamental idea in geometry; represented by a dot and named with a capital letter
Straight line
Shortest path connecting two points; continues forever in opposite directions; infinite number of points; named by any two points on the line
Line segment
A piece of a line; two endpoints
Ray
One endpoint; continues forever in one direction; half-line
Angle
Formed by two rays that start from the same point called the vertex
Adjacent Angles
Any angles that share a common side and a common vertex
Right angle
90 degree angle
Acute angle
Less than 90 degrees
Obtuse angle
Larger than 90 degrees but less than 180 degrees
Straight angle
Measure of 180 degrees (line)
Complementary Angles
Two angles who add up to 90 degrees
Supplementary angles
Two adjacent angles that form a straight line (sum of 180 degrees)
Angle Bisector
A ray from the vertex of an angle that divides the angle into two equal pieces
Vertical angles
Angles that are opposite of each other
**always equal
Adjacent angles
Share a common side and vertex
Intersecting lines
Two or more lines that cross each other at a point
Perpendicular lines
Two lines that meet to form right angles (90 degrees)
Parallel lines
Two or more lines that remain the same distance apart at all times
**never meet
Transversal
A third line that cuts two parallel lines
Polygons
A closed figure formed with line segments which are called the sides
Triangle
Three-sided polygon; three angles in its interior; sum of angles is always 180 degrees
Equilateral Triangle
All three angles are the same, all three sides are the same (Each is 60 degrees)
Isosceles Triangle
At least two sides are equal in length; angles opposite the equal sides will have equal measure
Scalene Triangle
All three sides are different lengths; all angles have different measures; largest angle will be opposite the largest side; smallest opposite the shortest
Equiangular triangle
All of its angles are equal measure; all 60 degrees; equilateral
Acute Triangle
Each of its angles with measures less than 90 degrees
Obtuse triangle
Has one of its angles with a measure greater than 90 degrees
Right triangle
One of its angles with a measure equal to 90 degrees
Altitude (height)
Segment that goes from a vertex of the triangle and makes a 90 degree angle with the opposite side known as the base
Median
A segment that goes from one vertex of a triangle to the midpoint of the opposite side
Angle Bisector
Segment that goes from one vertex of a triangle and divides the angle at the vertex into two smaller but equal angles
45-45-90 Right Triangle
Isosceles right triangle; if each of the sides that form the right angle has a measure of 1, then using Pythagorean theorem, find the hypotenuse
30-60-90 Right Triangle
Special right triangle; equilateral triangle cut in half
