Unit 2: Lesson 2: Points, Lines, and

Question 1

What is an angle

Answer 1

the figure formed by two lines extending from the same point

Question 2

What is an arc?

Answer 2

a part of the circumference of a circle or other curve

Question 3

What is a parallel line

Answer 3

a straight line that always remains the same distance from another line and, therefore, never intersects it

Question 3

What is a circle?

Answer 3

a closed plane curve with every point on the curve equidistant from a fixed point within the curve

Question 4

What is a line

Answer 4

a straight figure that has no thickness and extends infinitely in two opposite directions

Question 5

What is a line segment

Answer 5

the finite section of a line between two points on that line

Question 6

What is a perpendicular line

Answer 6

a line that intersects another line at a 90 degree angle

Question 7

What is a point

Answer 7

– a geometric element that has zero dimensions and a location determinable by an ordered set of coordinates

Question 8

What are angles made of

Answer 8

Angles are made of two intersecting lines and share a common point.

Question 9

What do angles measure

Answer 9

Angles measure the space between two intersecting lines and are measured in degrees.

Question 10

Measuring an angle allows you to see what

Answer 10

Measuring an angle allows you to see how far apart two objects are.

Question 11

What are the four undefined notions in geometry?

Answer 11

The undefined notions in geometry are point, line, distance along a line, and distance around a circular arc.

Question 12

“The set of all points that are equidistant from a central point” is the precise definition of which key concept?

Answer 12

It is the precise definition of a circle.

Question 13

conjecture

Answer 13

a statement that is made based on observations but is not yet proven

Question 14

definition

Answer 14

a statement that determines the meaning of a term or concept and describes what it is

Question 15

Euclidean geometry

Answer 15

the geometry based on Euclid’s axioms

Question 16

postulate

Answer 16

a statement that is accepted as true and has not been proved

Question 17

theorem

Answer 17

a statement that has been proved to be true using arguments and facts that are accepted as true

Question 18

undefined term

Answer 18

a term that does not need to be defined because it is explained using examples and descriptions, such as point, line, plane, and space

Question 19

undefined terms examples

Answer 19

point
line
plane
space