An angle that measures less than 90 degrees.
Acute angle
A triangle with all equal sides and angles.
Equilateral triangle
A figure with four angles.
Quadrangle
A synonym for congruent.
Equal, same size/shape, identical
An angle with a measure of exactly 90 degrees.
Right angle
A triangle that has at least two sides that are equal.
Isosceles triangle
A figure with at least one pair of parallel sides.
Square, rectangle, trapezoid, rhombus, ...
What is the measure of Angle x?
15 degrees
An angle that has a measurement greater than 90 degrees but less than 180 degrees.
Obtuse angle
A triangle with three sides that are all different lengths.
Scalene triangle
A polygon that has all equal sides.
Regular polygon
Angles 1 and 3 are called ____ or ____ angles because they are across from each other.
vertical or opposite
An angle with a measure of exactly 180 degrees.
Straight angle
The sum of the interior angles of a triangle.
180 degrees
A figure with five sides of equal length.
Regular pentagon
Angle a and Angle b are called ______ angles because they share a side.
adjacent
An angle that measures greater than 180 degrees but less than 360 degrees.
Reflex angle
The measure of each angle of an equilateral triangle.
60 degrees
A figure with a set of parallel and a set of perpendicular lines.
Rectangle
Repeated shapes that cover a surface with NO gaps or overlaps between shapes.
Tessellation