3rd grade rectilinear area worksheets

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Rectilinear area worksheets for third grade show L-shaped figures with all six sides labeled in centimeters. Your child finds each area by splitting the shape into two rectangles and adding, or by subtracting the cut-away notch from the full rectangle.

Free printable PDF worksheet, aligned to Common Core 3.MD.C.7.d.

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The kind of problems you'll get

Find the area of each figure. Show your work and include square units.

  1. Two rectangles have areas of 6 and 4 square units. Find their combined area.

    Answer: 10 square units.

Most problems on this sheet sit beside a picture, model or diagram, so this is the worked example the sheet itself prints. The answer key on page two prints the answer under every problem.

Every print pulls a fresh set of problems at this level, so a make-up test or a second sibling never gets the same sheet.

What's on a 3rd grade sheet

Every version prints on US Letter or A4, with its answer key after the problems.

How to teach this

Have your child draw one straight line that cuts the L into two rectangles before touching any numbers, then write a separate multiplication for each piece. If subtracting feels more natural, sketch the missing corner back in with a dotted line and take it away from the big rectangle. On the first figure, try both strategies. Matching answers is the best confidence builder there is.

Watch for: Kids multiply the two biggest labels and stop. The notch has to come off, or split the shape into two rectangles and add the parts. Kids add up all six side labels. That's the perimeter recipe, and area needs multiplying.

Common questions about 3rd grade rectilinear area

What kinds of figures are on the sheet?
Every item is an L-shaped figure with all six sides labeled in centimeters. Your child works out the total area and writes it on the line, like 36 sq cm.
Which strategy should my child use?
Either one: split the L into two rectangles and add, or find the full rectangle and subtract the notch. Solving one figure both ways is a great self-check.

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Aligned to Common Core 3.MD.C.7.d. Reviewed by the One more sheet team. Content version 241, updated September 2026.

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