Name:
Scheitlin Geometry CP
19
Prove it’s a…
Objective: Students will be able to prove a quadrilateral is a parallelogram, rhombus, rectangle, or square.
Do Now: If you know that a quadrilateral is a parallelogram, what properties does it need to have to be a…
Rhombus?
Rectangle?
Square?
1. All the sides are congruent.
1.
At least one of the properties of a
rhombus and one of the
2.
2.
properties of a rectangle.
3.
(Hint: Look on page #16)
If you want to prove a quadrilateral is a parallelogram, you need to use one of the methods below.
Circle one of the methods. Copy my example in the I do column (yellow paper). Then, try the You do column.
I do: Prove that the quadrilateral below is a
parallelogram.
You do: Prove that the quadrilateral below is a
parallelogram.
Name:
Scheitlin Geometry CP
19
You can see that the I do parallelogram is a square. To prove that it is a square, we need to prove it is a rhombus and a
rectangle.
How can I prove a parallelogram is a rhombus?
 Method 1:

Method 2:

Method 3:
I do: Prove that the shape is a rhombus. (Choose one of
the pink methods.)
How can I prove a parallelogram is a rectangle?
 Method 1:

Method 2:
I do: Prove that the shape is a rectangle. (Choose one of
the orange methods.)
Since I have proved that the shape is a rhombus and a rectangle, I know that it is a ___________.
What type of shape is your parallelogram from the front? Prove it using one of the methods!
You do: