Unit 8 - Quadrilaterals Flashcards
What is a trapezoid? (3)
- A quad that has AT LEAST one pair of parallel sides
- Parallel Sides = Bases
- Nonparallel Sides = Legs
What are the three main points that proves an isosceles trapezoid?
- Must have at least one pair of congruent opposite sides
- Each pair of base angles are congruent
- Diagonals are congruent
Why do you only have to prove only one set of base angles to be congruent in a proof?
Other angles are congruent thru consecutive interior angles
What is the trapezoid midsegment/median theorem? (4)
- Midsegment and Median are the same
- Midsegment is parallel to the base
- It’s measure is 1/2 of the sum of the bases
- Essentially, it is taking the average of the bases
What are the 4 properties of a parallelogram?
NOTE: PARALLELOGRAM IS A TRAPEZOID, NOT AN ISOCELES TRAPEZOID
- Opp. Sides are parallel
- Opp. Sides are congruent
- Opp. angles are congruent
- Diagonals bisect each other
Why does a rt. angle in a parallelogram mean the other 3 angles are also right? (2)
- Opp. Angles are congruent, making the other angle rt.
- Consecutive Interior forces the other angles to be rt.
What is the rule when it comes to the diagonals of a parallelogram? (2)
- Diagonals of a Parallelogram Bisect Each Other
- Diagonals form two congruent triangles (YOU WILL STILL HAVE TO PROVE)
What are the five ways to prove a parallelogram?
- Both pairs of opp. sides are congruent
- Both pairs of opp. sides are parallel
- Both pairs of opp. angles are congruent
- Diagonals bisect each other
- ONE pair of opp. sides are parallel & congruent
What is something to keep in mind with when proving properties of a quadrilateral?
You may use all the properties that the quadrilateral posess except for the properties you are trying to prove.
When you are stating that something is a parallelogram, rectangle etc., what do you put in the reason box?
A quadrilateral with (property) is a (parallelogram, rectangle, isoc. trapezoid, etc.)
What should you do when proving a rectangle? (2)
Prove that is a parallelogram first, then use the following two properties to prove that the parallelogram is a rectangle:
- One right angle (rect. has 4 rt. angles)
- Diagonals are congruent (rect. is also an isoc. trapezoid)
What are the properties of a rectangle? (5)
- Diagonals are congruent
- Diagonals bisect each other (can form isosceles triangles)
- Opposite sides are congruent
- Opposite sides are parallel
- Has 4 right angles (all angles are congruent)
What are the properties of a rhombus? (5)
- Opposite Sides are Parallel
- ALL sides are congruent
- Diagonals are angle bisectors
- Diagonals bisect each other
- Diagonals are perpendicular
What are the properties of a square? (7)
- ALL sides are parallel
- ALL sides are congruent
- ALL angles are right
- Diagonals are angle bisectors
- Diagonals bisect each other
- Diagonals are congruent
- Diagonals are perpendicular
How do you prove a rhombus? (4)
- Must prove it is a parallelogram first
- Diagonals are perpendicular
- Pair of consecutive sides are congruent
- A diagonal bisects one set of angles