Determine whether the statement is true or false. Explain or show your reasoning.
The shape is a rectangle.
The shape is a square.
The shape is a rhombus.
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Solution
False. Sample response: The angles are not right angles so it is not a rectangle.
False. Sample response: The sides are the same length but the angles are not right angles so it is not a square.
True. Sample response: It is a rhombus because all 4 sides are the same length.
Problem 2
Draw a trapezoid that is also a parallelogram. Explain how you know it is a trapezoid and a parallelogram.
Draw a trapezoid that is not a parallelogram. Explain how you know it is a trapezoid but not a parallelogram.
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Solution
Sample response:
It is a trapezoid because the two horizontal sides are parallel. It is a parallelogram because the lines containing the other two sides are also parallel.
It is a trapezoid because the two horizontal sides are parallel. It is not a parallelogram because the vertical side is not parallel to the slanted side.
Problem 3
Determine if it’s possible to draw each shape so it contains the 2 sides drawn on the grid. Explain your reasoning.
a square
a rectangle
a rhombus
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Solution
No. Sample response: The angle made by sides that are given is not a right angle.
No. Sample response: The same reason as for the square.
Yes. Sample response: I drew a quadrilateral with 4 equal sides so it's a rhombus.
Problem 4
Decide if each statement is true or false. Explain or show your reasoning.
A parallelogram is sometimes a rhombus.
A rhombus is always a parallelogram.
A trapezoid is never a rectangle.
A rectangle is never a square.
A parallelogram is always a trapezoid.
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Solution
True. Sample response: When the four sides of a parallelogram are equal, then it is a rhombus.
True. Sample response: The opposite sides of a rhombus are always contained in parallel lines.
False. Sample response: A trapezoid can be a rectangle if it has 4 right angles.
False. Sample response: A rectangle is a square when it has 4 equal sides.
True. Sample response: A parallelogram always has 2 pairs of parallel sides and a trapezoid has at least one pair of parallel sides. (Note: this is false if the definition of trapezoid is a quadrilateral with exactly one pair of parallel sides)
Problem 5
Draw a right triangle on the grid to match each description. If you think there is no such triangle, explain why.
It has 2 equal side lengths.
It has 3 equal side lengths.
It has 3 different side lengths.
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Solution
Sample responses:
See sample drawing.
This is not possible. The angles in a triangle with 3 equal sides are never right angles.
See sample drawing.
Problem 6
Jada cut a quadrilateral in half, from 1 vertex to the opposite vertex, and she got 2 triangles that each have exactly 2 equal side lengths. What kind of quadrilateral could Jada have cut in half? Explain or show your reasoning.
Elena put together 2 right triangles to make a quadrilateral. What kind of quadrilateral could Elena have made? Explain or show your reasoning.
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Solution
Sample response:
It could be a square or a rhombus. It could also have been a shape that does not fit any of the categories we looked at.
She could get a rectangle or a square. She could also get a parallelogram or a trapezoid or a shape that does not fit any of the categories we studied.
Problem 7
Can you draw a square on the grid that does not have a vertical or horizontal side? Explain or show your reasoning.
Draw the line segment from (4,4) to (6,5). Can you draw a square that contains this segment as one of its sides? Explain or show your reasoning.
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Solution
Sample responses:
This is a square because the four sides are equal and the four angles are right angles. The sides are equal because they all go from one corner of a grid square to the opposite corner. I sketched the shape on patty paper to check that the angles are all right angles.
Yes, this is a square because each side is the diagonal of a 2 unit by 1 unit rectangle. Then I checked that the angles are all 90 degrees.