Rectangle area by multiplying
Multiply side lengths to find areas of rectangles and represent whole-number products as rectangular areas
What a learner can do afterwards
- Calculate the area of a 7 cm × 9 cm rectangle as 63 cm²
- Draw a rectangle with area 36 square units and label its side lengths
- Solve: A garden is 8 m by 5 m. What is its area?
1 · Read
You already know how to find area by counting unit squares one at a time. There is a faster way. If you know the length and the width of a rectangle, you can multiply them to get the area right away.
A rectangle is 7 cm by 9 cm. Multiply the side lengths: 7 × 9 = 63. The area is 63 square centimeters, written as 63 cm².
Always write the unit name after the number, like cm² or m². The small 2 means the squares fit inside the shape, not just a length measured across.
To find area, multiply the two side lengths and label the answer in square units, like cm² or m².
More to read
Area of rectangles review
Rectangles multiply their sides into area. A 7 cm by 9 cm rectangle covers 63 square centimetres because 7 x 9 = 63. Sides times sides is the whole rule. Do not add the sides, and do not guess. Draw the rectangle and label both sides before multiplying. Labels stop sideways slips like 7 x 6. Finish with square units always. Numbers without squares are just lengths in disguise.
How to Find the Area of a Rectangle: Formula & Review
The formula never varies: length times width. An 8 m by 5 m garden covers 40 square metres because 8 x 5 = 40. Measure in matching units first: metres with metres, centimetres with centimetres. Mixed units break the multiply. One formula, one multiply, one square unit label. That rhythm areas every rectangle from stamps to gardens.
How to Find the Area and Perimeter of a Rectangle: 8 Steps
Area and perimeter are easy to mix, so learn both side by side. Area multiplies: 8 by 5 gives 40 square metres. Perimeter walks the edge: 8 + 5 + 8 + 5 gives 26 metres. Different jobs, different tools, different units. Ask which one the question wants before computing. Cover words mean area. Fence words mean perimeter. Nouns guide the maths.
Key ideas: find all possible side lengths of rectangles with a given area
One area can wear many side pairs. Area 36 fits 4 by 9, 6 by 6 and 3 by 12, because each pair multiplies to 36. Listing factor pairs finds them all. Start at 1 and climb: 1 by 36, 2 by 18, 3 by 12, 4 by 9, 6 by 6. Stop when pairs repeat mirrored. Drawing each pair proves it fits. Same cover, different frame.
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2 · Watch
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Where this leads
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.