Angles Vocabulary
What do you call an angle less than 90°?
Acute angle
A triangle with all sides equal is called what?
Equilateral triangle
Angles across from each other when two lines cross are?
Vertical angles
What is the sum of the interior angles of a triangle?
180 degrees
True or False: All equilateral triangles are also acute.
True
What is a 90° angle called?
Right angle
A triangle with two equal sides is called what?
Isosceles triangle
Angles next to each other that form a straight line?
Linear pair
If one angle in a triangle is 50°, and another is 60°, what’s the third?
70°
A triangle has angles 40° and 90°. What type is it?
Right triangle
What do you call an angle more than 90° but less than 180°?
Obtuse angle
A triangle with all different side lengths is called?
Scalene triangle
Angles on the same side of a transversal, inside two lines?
Same-side interior angles
What do the exterior angles of a triangle add up to?
360 degrees
If a triangle has one obtuse angle, what must the other two be?
Acute angles
What is a straight angle’s measure?
180 degrees
A triangle with one 90° angle is what type?
Right triangle
Angles on opposite sides of a transversal, inside two lines?
Alternate interior angles
What’s the Triangle Inequality Theorem?
The sum of any two sides must be greater than the third
A triangle has angles 30°, 60°, and __. Fill in the blank.
90°
Angles that add up to 90° are called what?
Complementary angles
Can a triangle have more than one right angle?
No
What’s the relationship between vertical angles?
They are equal
Can a triangle have angles that add to more than 180°?
No
What do you call a triangle with all three angles less than 90°?
Acute triangle