Plainfield Board of Education
Office of Elementary Mathematics
Name: _____________________________________
Date: ________________
Teacher: ___________________________________
Grade 3
Unit 7 Assessment - Reasoning about Two-dimensional Shapes – Answer Key
Section 1
1. Circle the three quadrilaterals below.
(3.G.1)
2. The triangle below has 3 equal sides.
(3.MD.8)
What is the length of each side if the perimeter is 27 cm? Enter your answer in the box.
9
cm
Plainfield Board of Education
Office of Elementary Mathematics
3. The shape below has two pairs of opposite sides which are parallel. Circle two names
that are used to describe this shape.
(3.G.1)
A. quadrilateral
B. square
C. parallelogram
D. hexagon
4. Katherine draws a square with an area of 25 square cm. What is the perimeter of the
square?
(3.MD.8)
Enter your answer in the box.
20
cm
Plainfield Board of Education
Office of Elementary Mathematics
5. Circle the two figures that have a perimeter of 14 units. Put an X on the figure that
has the largest perimeter.
(3.MD.8)
Plainfield Board of Education
Office of Elementary Mathematics
6. Select the three shapes that always have at least one pair of parallel sides.
(3.G.1)
A. triangle
B. rhombus
C. trapezoid
D. rectangle
E. quadrilateral
7. Select the two shapes that always have at least one right angle.
A. triangle
B. rectangle
C. trapezoid
D. rhombus
E. quadrilateral
F. right triangle
(3.G.1)
Plainfield Board of Education
Office of Elementary Mathematics
8. The shape below has a perimeter of 22 inches.
(3.MD.8; 3.G.1)
3 inches
4 inches
6 inches
4 inches
? inches
figure not drawn to scale
What is the length of the missing side? Enter your answer in the box.
5
inches
What is the name of the polygon above? Enter your answer in the box.
Plainfield Board of Education
Office of Elementary Mathematics
1
of the whole rectangle.
6
There are 3 squares in each row. How many squares are in the whole rectangle? You
may use the grid to draw the shape.
(3.G.2)
9. A rectangle is divided into equal squares. One row covers
A. 6 squares
B. 9 squares
C. 12 squares
D. 18 squares
10. Partition the hexagon into 6 equal parts and shade in
1
of the area of the hexagon.
6
(3.G.2)
Plainfield Board of Education
Office of Elementary Mathematics
11. A rectangle is divided into 2 rows of 3 equal squares. What fraction of the whole
rectangle is each square?
(3.G.2)
Enter your answer in the box
12. Partition the rectangle below into equal parts and shade
3
of the rectangle.
8
(3.G.2)
Plainfield Board of Education
Office of Elementary Mathematics
Section 2: Open Ended Response
Your dad is building you a rectangular sandbox. He wants the sandbox to have an area of
24 square feet, but he wants you to decide how long and wide to make the sandbox.
(3.MD.8; 3.G.2)
a. Use the grid below to design a plan that your dad could use for the sandbox.
Label your plan with the length and width and find the perimeter.
b. Plan: length: _________
width: _________
c. Partition your rectangle into 4 equal parts and shade
Each square is 1 unit
perimeter: ________
1
of the rectangle.
4