Types of Angles
An angle measuring 35° is this type of angle.
Acute
Two angles share the same vertex and one common side. What relationship do they have?
Adjacent
Two angles add to 90°. What are they called?
Complementary
When parallel lines are cut by a transversal, angles in the same relative position are called these.
Corresponding
Co-interior angles between parallel lines add to this amount.
180°
What type of angle is 180°?
Straight
Two lines cross. One angle is 72°. What is the vertically opposite angle?
72°
One complementary angle is 38°. Find the other angle.
52°
Two corresponding angles are formed by parallel lines. One is 64°. Find the other.
64°
One co-interior angle is 115°. Find the other angle.
65°
An angle measuring 125° is this type of angle.
Obtuse
Two vertically opposite angles are labelled 3x° and 75°. Find x.
x=25
Two complementary angles are x° and 2x°. Find x.
x=30
Two alternate angles are labelled 4x° and 80°. Find x.
x=20
Co-interior angles are x° and 2x°. Find x.
x=60
Name the angle type: greater than 180° but less than 360°.
Reflex
One angle at an intersection is 128°. Find the other three angles.
128°, 52°, 128°, 52°
Supplementary angles are 2x° and 4x°. Find both angles.
x=30;
60°, 120°
Corresponding angles are (3x+5)° and 80°. Find x.
x=25
Co-interior angles are (2x+10)° and (3x−5)°. Find x.
x=35
An angle is twice its supplementary angle. Find both angles and classify them.
120° obtuse, 60° acute
Two lines intersect. One angle is (4x+10)° and its adjacent angle is (2x+20)°. Find x and all four angles.
x=25;
110°, 70°, 110°, 70°
One supplementary angle is three times the other. Find both angles.
45°, 135°
Two alternate angles are (5x−20)° and (3x+30)°. Find x and both angles.
x=25;
105°
Two parallel lines are cut by a transversal. One angle is 68°. Give the sizes of all eight angles formed.
Four 68° angles and four 112° angles