 Polygon – a closed many straight-sided figure.

 Angle – is a figure formed by two non-collinear rays that meet at a common end point.

 Degree – a unit of measurement of an angle or arc, represented by the symbol º. 120º

Definition  Right Angle – an angle whose measure is exactly 90°.Also define as an angle formed by 2 perpendicular lines.

Definition  Perpendicular lines – are two lines intersecting at right angles.  For example,  ray EP & ray ET. P ET

parallelogram rectangle rhombus square trapezoid

 Quadrilateral –  it refers to any four-sided figure.  a polygon with 4 angles and 4 straight sides.

Quadrilaterals are classified either: Concave or non- Convex Quadrilateral -a quadrilateral whose diagonals don’t intersect -Convex Quadrilateral - a quadrilateral whose diagonals intersect

 You can name a quadrilateral the right as:  ROSE or OSER or SERO or EROS  Or RESO or ESOR or SORE  But not,  ROES or OESR or SEOR or ERSO RO E S

A quadrilateral has the following parts: 4 sides 4 vertices 4 angles 2 diagonals

Take a look at quadrilateral LOVE. L O E V The sides are: LO, OV,VE,EL

Take a look at quadrilateral LOVE. L O E V The vertices are: L, O,V,E

Take a look at quadrilateral LOVE. L O E V The angles are:  L,  O,  V,  E

Take a look at quadrilateral LOVE. L O E V The diagonals are: LV & OE

Opposite sides: two sides having no common endpoints Consecutive sides: two sides with a common endpoint Consecutive angles: two angles with a common side Opposite angles: two angles having no common sides Consecutive vertices: two vertices with a common side Opposite vertices: two vertices having no common sides Diagonal: line segment joining the vertices of opposite Diagonal: line segment joining the vertices of opposite angles

Take a look at quadrilateral LOVE. L O E V The consecutive sides are: LE & LO LO & OV,OV &VE, VE & EL Consecutive sides: two sides with a common endpoint

L O E V The opposite sides are: LO & EV, OV & LE Opposite sides: two sides with no common endpoint

Consecutive angles- two angles with a common side. L O E V The consecutive angles are:  L &  E  L &  O,  O &  V,  V&  E

Opposite angles- two angles with no common side. L O E V The opposite angles are:  L &  V,  O &  E

Consecutive vertices- two vertices with a common side. L O E V The consecutive vertices are: L & E L & O, O & V, V& E

Opposite vertices- two vertices with no common side. L O E V The opposite vertices are: L & V, O & E

Name the following parts: - 2 pairs of opposite sides - 4 pairs of consecutive vertices -4 pairs of consecutive angles K I N D

 The sum of all the angles equals 360º degrees. A m  A+ m  B +m  C + m  D =360 B C D

 The sum of all the angles equals 360º degrees. 90º + 360º

 The sum of all the angles equals 360º degrees. Copyright © 2000 by Monica Yuskaitis 90º + 360º

 The sum of all the angles equals 360º degrees. 70º 110º 70º 110º 70º 110º + 360º

 The sum of all the angles equals 360º degrees. 65º 115º65º 115º 65º 115º + 360º

90º ? ? 360º +

70º ? 110º 70º 110º ? + 360º

65º 115º65º ? 115º ? + 360º

90º ? ? + 360º

58º 81º 109º ? + 360º 81º58º 109º ?

Copyright © 2000 by Monica Yuskaitis

trapezium No parallel sides

Answer each question as indicated. What is a quadrilateral?

Answer each question as indicated. What is the sum measures of the interior angles of a quadrilateral? Answer: 360 