angles and parallel lines

• If two lines are perpendicular, then they form four right angles at their point of intersection.
• what is a point?


  it has a position and has no size
• what is a line?


  A line extends infinitely in both directions and has an infinite number of points
• what is a line segment?


  A line segment is a part of a line that is bounded by two distinct endpoints and has length
• what is a ray?

  A ray is a part of a line that has one endpoint and extends infinitely in one direction.
• what is a point of intersection?


  a point where two lines meet
• what is a plane?


  A flat surface in three-dimensional space. it has no thickness
• what is the point where two line segments meet called?


  a vertex
• what unit is used to measure angles?


  Degrees
• how many degrees is one circle?

  360
• how many degrees is half of a circle?

  180 degrees
• what are acute angles?


  Angles less than 90 degrees.
• what are right angles?

  90 degrees
• What are obtuse angles?


  Angles greater than 90 degrees.
• what are reflex angles?

  Angles greater than 180 degrees.
• what are complementary angles?


  Two angles that add up to 90 degrees.
• what are adjacent angles?


  Adjacent angles are angles that are side by side
• what are supplementary angles?

  Two angles that add up to 180 degrees.
• what do angles on a straight line add up to?

  180 degrees
• what do angles at a point add up to?

  360 degrees
• what are vertically opposite angles?


  they are equal and opposite each other, created by two straight intersecting lines
• what do adjacent angles on a straight line add up to?

  180 degrees
• what are parallel lines?


  Lines that never intersect.
• lines that are not parallel will meet at a certain point
• parallel lines are always straight
• what symbolises parallel lines?

  arrows
• what is a transversal?


  A line that intersects two or more other lines.
• how many angles are formed at each point of intersection?

  4
• what are interior angles?


  they add up to 180
• what are exterior angles?

  angles that are parallel to the inner angles of a polygon but lie on the outside of it
• what are alternate angles?

   angles that occur on opposite sides of the transversal line and have the same size
• what are corresponding angles?

  the angles which are formed in matching corners or corresponding corners with the transversal when two parallel lines are intersected by any other line