Download A line segment is a part of a straight line between two

Math 4. Class work 27.
Review of geometry.
1. There are four undefined terms in geometry: a point, a line, a plane, and a
distance between two points. These terms are considered to be intuitively
understood.
2. All other concepts and terms we can define based on these four, for example
A line segment is a part of a straight line between two chosen points.
(A set of points of a straight line between two points.)
These points are called endpoints.
A ray is a part of a straight line consisting of a point (endpoint) and all
points of a straight line at one side of an endpoint. Ray is named by two ints
endpoint and any other point, ray ሬሬሬሬሬԦ
𝐴𝐵 or AB ( where A is an endpoint)
A circle is the set of all points in a plane that are at a given distance from a
given point, the center.
Parallel lines are lines in a plane which do not meet; that is, two lines in a plane
that do not intersect or touch each other at any point are said to be parallel.
Draw a circle and a straight line.
3.
An angle is the figure formed by two rays, called the sides of the angle,
sharing a common endpoint, called the vertex of the angle.
Two angles are called
adjacent if they have a
common vertex and a
common side. If two
adjacent angles combined
form a straight angle they
are called supplementary, if
they form a right angle than
they are called complementary.
When two straight lines intersect at a point, four angles are formed. A pair of angles
opposite each other, formed by two intersecting straight lines that form an "X"-like
shape, are called vertical angles or opposite angles or vertically opposite angles.
 and  and  and  are 2 pairs of vertical
angles.
Vertical angle theorem:
vertical angles are equal
4. Sum of the internal angles of a triangle is
always equal to 180.
5. Sum of the internal angels of any polygon is (𝑛 − 2) × 180.
𝑛 × 180 − 360 = (𝑛 − 2) × 180
6. Construction with a compass and a straight edge.
a. Draw a triangle with the sides are equal to the segments.
b. Divide the segment by half.