This grade 3 perimeter worksheet gives 23 problems on perimeter, ordered from easy to hard, with a separate answer key.
These 23 problems practice perimeter: adding side lengths of polygons, finding unknown sides and comparing rectangles that have the same perimeter or the same area (3.MD.D.8). They start with simple shapes and end with word problems that need more than one step.
Grade 3 Perimeter Worksheet: problems 1–5
Problem 1: Perimeter of a triangle
Find the perimeter of the triangle.
Problem 2: Perimeter of a rectangle
Find the perimeter of the rectangle.
Problem 3: Perimeter of a square
A square garden bed has sides that are each 8 feet long. Find its perimeter.
Problem 4: Perimeter of a trapezoid
Find the perimeter of the trapezoid.
Problem 5: Perimeter of a pentagon
A pentagon has sides of 7 cm, 5 cm, 6 cm, 8 cm and 4 cm. Find its perimeter.
Grade 3 Perimeter Worksheet: problems 6–10
Problem 6: Regular hexagon
All sides of a regular hexagon are equal. Find the perimeter of this hexagon.
Problem 7: Rectangle from numbers
A rectangle is 12 feet long and 7 feet wide. Find its perimeter.
Problem 8: Equal sides
A triangle has three sides that are each 10 inches long. Find its perimeter.
Problem 9: Count the units
Find the perimeter of the shape. Each side of a square is 1 centimeter.
Problem 10: Missing side of a triangle
The perimeter of the triangle is 24 meters. Find the missing side length.
Grade 3 Perimeter Worksheet: problems 11–15
Problem 11: Missing width
The perimeter of the rectangle is 30 feet. Find the missing width.
Problem 12: Side of a square
A square has a perimeter of 36 inches. How long is each side?
Problem 13: Missing side of a quadrilateral
A quadrilateral has a perimeter of 40 cm. Three of its sides are 11 cm, 9 cm and 12 cm. Find the fourth side.
Problem 14: Missing length
A rectangle has a perimeter of 44 feet and a width of 8 feet. Find its length.
Problem 15: Same perimeter
The three rectangles are drawn on unit squares. Find the perimeter and the area of each rectangle.
Grade 3 Perimeter Worksheet: problems 16–20
Problem 16: Compare two rectangles
Rectangle A is 8 cm by 2 cm. Rectangle B is 6 cm by 4 cm. Show that they have the same perimeter, then find which has the greater area.
Problem 17: Same area, different perimeters
All three rectangles have an area of 12 square units. Find the perimeter of each one.
Problem 18: Fence for a yard
Jamal puts a fence around a rectangular yard that is 15 feet long and 10 feet wide. How many feet of fence does he need?
Problem 19: Walk around the park
A triangular park has sides of 120 yards, 150 yards and 90 yards. Mei walks once around the park. How far does she walk?
Problem 20: Ribbon for a frame
Aisha wants to glue ribbon around the edge of a picture frame that is 11 inches long and 9 inches wide. She has 36 inches of ribbon. Does she have enough? If not, how much more does she need?
Grade 3 Perimeter Worksheet: problems 21–23
Problem 21: Square pen
Diego uses 48 feet of fencing to make a square pen for the farmers market. How long is each side of the pen?
Problem 22: Find the mistake
Liam says the perimeter of a rectangle that is 8 inches long and 5 inches wide is 13 inches. Explain his mistake and find the correct perimeter.
Problem 23: Banner at the market
Maya’s banner is a rectangle with a perimeter of 34 feet. Its width is 7 feet. Find its length, then find how many feet of rope go around it twice.
How to use this grade 3 perimeter worksheet
Print this grade 3 perimeter worksheet as a PDF, solve every problem on paper, then compare with the answer key.
See every chapter on the Grade 3 math page.
