Math Unit 7 Vocab

An angle measuring less than 90 degrees

Acute angle

An angle measuring exactly 90 degrees.

Right angle

An angle measuring greater than 90 degrees and less than 180 degrees.

Obtuse angle

An angle measuring exactly 180 degrees

Straight angle

Angles with equal measures

Congruent Angles

Point where two lines meet forming an angle

Vertex

Side in common

Ray

Two angles that share a vertex, share a ray, have no common interior points (don’t overlap).

Adjacent Angles

Opposite pair of angles (non-adjacent) formed when two lines intersect.  They share a vertex.  Vertical angles are always congruent.

Vertical Angles

Two angles whose measures sum to 90^o

Complementary Angles

Two angles whose measures sum to 180

Supplementary Angles

Two adjacent angles formed by a ray (or line) and a straight angle.  Linear pairs are supplementary.

Linear Pair

Tool used to measure the number of degrees in an angle

Protractor

All angles acute

Acute triangle

One right Angle

Right triangle

One obtuse angle

Obtuse triangle

All angle congruent

Equiangular Triangle

All sides congruent

Equilateral Triangle

At least two sides congruent

Isosceles Triangle

No sides congruent

Scalene Triangle

The sum of the measures of interior angles of a triangle is 180

Triangle Sum Theorem

The measure of an exterior angle of a triangle equals the sum of the measures of its two remote interior angles

Triangle Exterior Angle Theorem

Cut in half (creating two equal halves)

Bisect

The sum of any 2 sides of a triangle must be greater than the measure of the third side.

Triangle Inequality Theorem

A line that intersects two lines at two different points

Transversal

If a transversal intersects two parallel lines, then corresponding angles are congruent

Corresponding Angles Postulate

If a transversal intersects two parallel lines, then alternate interior (or exterior) angles are congruent

Alternate Interior (or Exterior) Angles Theorem

If a transversal intersects two parallel lines, then same-side interior (or exterior) angles are supplementary

Same-side Interior (or Exterior) Angles Theorem