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3rd grade math · Unit 2: Lines, shapes, area, and perimeter

Area of an L shape

What this lesson shows

Split it into two rectangles and add the areas.

The worked example

The lesson works this one step by step: 6 by 8 and 4 by 5, side by side. Then your kid tries one like it on paper.

The steps

  1. Cut it in two
  2. Area of the left
  3. Area of the right
  4. Add the areas

Helping at home

Draw one straight line from the inside corner to cut the L into two rectangles. Write the sides of each rectangle, multiply each, and add the two areas. Answer in square feet.

If your kid gets stuck

Cut it into two rectangles first.

Watch it with Lux

With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.

See how Lux works

Standards

  • Common Core 3.MD.C.7d
    Recognize area as additive. Find areas of rectilinear figures by decomposing them into non-overlapping rectangles and adding the areas of the non-overlapping parts, applying this technique to solve real world problems.
Matches standards in 49 statesSee each state's code

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