Angles in Parallel Lines Flashcards
Angles that sum to 90 are called
complementary
Angles that sum to 180 are called ____
supplementary
Two angles on a straight line are called a ____
linear pair
Lines that never meet are called ____
parallel
Lines that meet at a right angle are called ____
perpendicular
A line that intersects (crosses) two or more other lines (often parallel lines) is called a ____
transversal
Parallel lines have so much in common!
It’s a shame that they will never ____
meet
These angles are ____ and they are ____
corresponding
equal / congruent
These angles are ____, they are ____
co-interior
supplementary (sum to 180)
These angles are ____, they are ____
alternate
equal / congruent
These angles are ____, they are ____
alternate exterior
equal / congruent
The interior angles of a triangle sum to ____
180 degrees
The interior angles of a quadrilateral add to ____
360 degrees
The interior angles of a pentagon add to ____
540 degrees
The exterior angles of any polygon sum to ____
360 degrees
A 2D shape is also known as a ____
plane figure (as in, a flat shape)
A 2D shape with 3 or more straight sides and angles is called a ____
polygon (poly means “many”)
Is a circle a polygon?
No, because it doesn’t have straight sides
What is the same and what is different about these two shapes?
They both have five sides, so they are both pentagons
The one on the left is a regular pentagon because all the sides and angles are the same, and the one on the right is irregular, because they are not the same.
What is the difference between these two polygons?
The one on the left is convex (all interior angles are less than 180) and the one on the right is concave (not all interior angles are less than 180)
These angles are ____, they are ____
vertical angles / vertically opposite angles
equal / congruent
angles that have a common vertex and a common side are called ____
adjacent angles
What is the name of this rule?
What is the relationship between the a, b, and d?
It’s called the exterior angle theorem.
d = a + b
The exterior angle of a triangle is equal to the sum of the two opposite interior angles
Name this angle
∠ABC or ∠CBA
m∠ABC
how do you express this angle notation in words?
“the measure of angle ABC”
It has no size or shape, no dimensions, just a position. What is it?
a point
A straight path of points that has no beginning or end. What is it?
a line
A portion of a line that has two endpoints. What is it?
a line segment
A line that has one endpoint and extends forever in the other direction
a ray
The point exactly in the middle of a line segment, exactly halfway between two points, is called a ____
midpoint
Two kinds of geometry are displayed here. What is the difference and what are they called?
On the left is “plane geometry”, the geometry of 2D shapes
On the right is “solid geometry”, the geometry of 3D shapes
when lines meet at a point to form an angle, we call that point ____
a vertex
