If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

3rd grade

Course: 3rd grade > Unit 11

Lesson 1: Perimeter
Math
3rd grade
Perimeter
Perimeter
© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

Find perimeter by counting unit squares

Google Classroom
Practice finding perimeter by counting unit squares.  We will start with rectangles and then try some irregular shapes.

Rectangles

Problem 1A
Each square on the grid is 1 unit square.
What is the perimeter of the rectangle?
A rectangle with 1 column and 4 rows on a grid. There are 4 unit squares in the rectangle.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
units

Problem 1B
Each square on the grid is 1 unit square.
What is the perimeter of the square?
A square with 4 rows and 4 columns shown on a grid. There are 16 unit squares in the square.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
units

Irregular shapes

Problem 2A
Each square on the grid is 1 unit square.
What is the perimeter of the shape?
A figure with 3 rows and 2 columns of 4 unit squares connected together on a grid. The top row has 2 columns of unit squares and the bottom 2 rows each have 1 unit square.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
units

Problem 2B
Each square on the grid is 1 unit square.
What is the perimeter of the shape?
A figure of 5 rows and 4 columns of 16 unit squares connected together on a grid. The top row has 2 columns of unit squares, the second, third, and fourth rows have 4 columns of unit squares, and the bottom row has 2 columns of unit squares.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
units

Want to join the conversation?

Log in