8-1
A series of points that extends in two opposite directions without end
What is a line?
A figure formed by two rays with a common endpoint
What is an angle?
Angles that are formed by intersecting lines, are opposite one another, and have equal measures
What are vertical angles?
A closed figure made of 3 line segments that meet at their endpoints
What is a triangle?
A triangle with one angle that measures 90 degrees
What is a right triangle?
Consists of two endpoints
What is a segment?
The point of intersection of two sides of an angle
What is a vertex?
Two angles that have a sum of 90 degrees
Three ways to classify triangles by their angles
What are acute, right, and obtuse?
A triangle that has two equal sides
What is an isosceles triangle?
Consists of one endpoint and a line that extends forever in the opposite direction
What is a ray?
Measures less than 90 degrees
What is an acute angle?
Angles that have a sum of 180 degrees
What are supplementary angles?
Three ways to classify triangles by their sides
What are equilateral, isosceles, and scalene?
A triangle with one angle that is more than 90 degrees
What is an obtuse triangle?
Lines that cross one another
What are intersecting lines?
Measures more than 90 degrees
What is an obtuse angle
What are adjacent angles?
The sum of the three angles of a triangle is always equal to this
What is 180 degrees?
A triangle that has three equal sides
What is an equilateral triangle?
Lines that never cross one another
What are parallel lines?
Measures 90 degrees
What is a right angle?
Angles with equal measures
What are congruent angles?
A triangle with 3 unequal sides
Scalene
A triangle that has three angles that measure less than 90 degrees
What is an acute triangle?