Properties of Quadrilaterals Flashcards
Properties of a parallelogram
- Opposites are parallel by definition
- Opposite sides are congruent
- Opposite angles are congruent
- Diagonals bisect each other
- Any pair of consecutive angles are supplementary
Properties of rectangles
[All the properties of a parallelogram apply by definition]
Opposites are parallel by definition
- Opposite sides are congruent
- Opposite angles are congruent
- Diagonals bisect each other
- Any pair of consecutive angles are supplementary
All angles are right angles
Diagonals are congruent
Properties of kites
- Two disjoint paris of consecutive sides are congruent by definition
- The diagonals are perpendicular
3.One diagonal is the perpendicular bisector of the other
4.One of the diagonals bisects a pair of opposite angles
5.One pair of opposite angles are congruent
Rules 3-5 are sometimes called the half properties of kites
Properties of rhombuses
[All properties of a parallelogram apply by definition]
Opposites are parallel by definition
-Opposite sides are congruent
-Opposite angles are congruent
-Diagonals bisect each other
-Any pair of consecutive angles are supplementary
[All the properties of a kite apply (the half properties of a kite become full properties)]
Diagonal is the perpendicular bisector of the other
4. of the diagonals bisects angles
5. opposite angles are congruent
All sides are congruent- that is, a rhombus is equilateral
-The diagonals bisect the angles
-The diagonals are the perpendicular bisectors of each other
-The diagonals divide the rhombus into four congruent right triangles
Properties of squares
[All the properties of a rectangle apply by definition]
All angles are right angles
Diagonals are congruent
All the properties of a parallelogram apply by definition
Opposites are parallel by definition
-Opposite sides are congruent
-Opposite angles are congruent
-Diagonals bisect each other
-Any pair of consecutive angles are supplementary
[All the properties of a rhombus apply by definition]
Diagonal is the perpendicular bisector of the other
4. of the diagonals bisects angles
5. opposite angles are congruent
All sides are congruent- that is, a rhombus is equilateral
-The diagonals bisect the angles
-The diagonals are the perpendicular bisectors of each other
-The diagonals divide the rhombus into four congruent right triangles
Properties of Isosceles trapezoids
- Legs are congruent by definition
- The bases are parallel by definition of a trapezoid
- The lower base angles are congruent
- The upper base angles are congruent
- The diagonals are congruent
- Any lower base angle is supplementary to any upper base angle
If the figure is an isosceles trapezoid, the following are T/F:
- The opposite sides are congruent
- Opposite sides are parallel
- The diagonals bisect the angles
- The diagonals bisect each other
- The diagonals are congruent
- T
- F
- F
- F
- T
With a kite, the following are T/F:
- The opposite sides are congruent
- Opposite sides are parallel
- The diagonals bisect the angles
- The diagonals bisect each other
- The diagonals are congruent
- The diagonals are perpendicular
- F
- F
- T/F
- T/F
- F
- T
What is an equilateral that is not equiangular
Rhombus
What is an equiangular quadrilateral that is not equiangular
Rectangular
Always true, sometimes true, or never true
- A square is a rhombus
- A rhombus is a square
- A kite is a parallelogram
- A rectangle is a polygon
- A polygon has the same number of vertices as sides
- A parallelogram has three diagonals
- A trapezoid has three bases
- Always
- Sometimes
- Sometimes- when a kite is a rhombus
- Always- A rectangle=parallelogram=quadrilateral
- Always- parallelograms only have 2
- Never
- Never
The following methods can be used to prove that a rhombus-like rectangle is a parallelogram. PROVING THAT A QUADRILATERAL IS A PARALLELOGRAM
- If both pairs of opposite sides of a quadrilateral are parallel, then the quadrilateral is a parallelogram (reverse of definition)
- If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram (converse of property)
- If one pair of opposite sides of a quadrilateral are both parallel and congruent, then the quadrilateral is a parallelogram
- If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram (converse of a property)
- If both pairs of opposite angles of a quadrilateral are congruent, then the quadrilateral is a parallelogram (converse of a property)
Prove that a quadrilateral is a rectangle
- Show that a quadrilateral is a parallelogram
- If a parallelogram contains at least one right angle, then it is a rectangle (reverse of definition)
You can also prove that a quadrilateral is a rectangle without first showing that it is a parallelogram
3. If all four angles of a quadrilateral are right angles, then it is a rectangle
Prove that a quadrilateral is a kite
- If two disjoint pairs of consecutive sides of a quadrilateral are congruent then it is a kite (reverse of the definition)
- If one of the diagonals of a quadrilateral is the perpendicular bisector of the other diagonal, then the quadrilateral is a kite
Proving that a quadrilateral is a rhombus
- Show that is is a parallelogram
- If if a parallelogram contains a pair of consecutive sides that are congruent, then it is a rhombus (reverse of definition)
- If either diagonal of a parallelogram bisects two angles of the parallelogram, then it is a rhombus
You can prove that a quadrilateral is a rhombus without first showing that it is a parallelogram
4. If the diagonals of a quadrilateral are perpendicular bisectors of each other, then the quadrilateral is a rhombus