Basic geometric concepts

What do you see in the diagram?

• Two lines are parallel.

• Two lines are intersecting.

• Two lines are skew.

• Two lines are perpendicular.

What do you see in the diagram?

• Line CD lies on plane S.

• Line segment CD lies on plane S.

• Line CD intersects plane S.

• Line segment CD intersects plane S.

What do you see in the diagram?

• Line

• A point and a line

• Ray

• Line segment

What kind of angle do you see in the diagram?

• Acute angle

• Obtuse angle

• Straight angle

• Concave angle

What kind of angle do you see in the diagram?

• Acute angle
• Obtuse angle
• Straight angle
• Right angle

What kind of angle do you see on the diagram?

• Right angle
• Obtuse angle
• Straight angle
• Acute angle

What kind of angle pairs are the angles marked in the diagram?

• Adjacent angles
• Complementary angles
• Corresponding angles
• Vertical angles

What kind of angle pairs are the angles marked in the diagram?

• Adjacent angles
• Complementary angles
• Corresponding angles
• Vertical angles

What kind of angle pairs are the angles marked with red in the diagram?

• Supplementary angles

• Complementary angles
• Corresponding angles
• Vertical angles