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Lesson 4: Multiply to find area

# Area of rectangles review

Review the basics of area of rectangles and try some practice problems.

## What is area?

Area is the space inside of a two-dimensional shape. We can also think of area as the amount of space a shape covers.
For example, the rectangle below has an area of 12 square units because it covers 12 square units.
A rectangle with 2 rows. Each row has 6 unit squares. The unit squares are labeled 1 through 12.

## Area of a rectangle formula

To find the area of a rectangle, we multiply the length of the rectangle by the width of the rectangle.
start text, A, r, e, a, space, o, f, space, r, e, c, t, a, n, g, l, e, end text, equals, start text, l, e, n, g, t, h, end text, times, start text, w, i, d, t, h, end text
Want to know why this formula works? Check out this video.

### Example 1:

A rectangle with 2 rows. Each row has 6 unit squares. The left side of the rectangle is labeled 2 units and the top side of the rectangle is labeled 6 units.
start text, A, r, e, a, end text, equals, start text, l, e, n, g, t, h, end text, times, start text, w, i, d, t, h, end text
empty space, equals, 6, times, 2
empty space, equals, 12, start text, space, s, q, u, a, r, e, space, u, n, i, t, s, end text

### Example 2:

A rectangle with the left side labeled 4 units and the top side labeled 7 units.
start text, A, r, e, a, end text, equals, start text, l, e, n, g, t, h, end text, times, start text, w, i, d, t, h, end text
empty space, equals, 7, times, 4
empty space, equals, 28, start text, space, s, q, u, a, r, e, space, u, n, i, t, s, end text

### Practice set 1: Multiply to find area

Problem 1A
• Current
What is the area of the rectangle?
A rectangle with the left side labeled 6 units and the top side labeled 5 units.
square units

Want to try some more area of rectangle problems? Check out this exercise:
Area of rectangles

### Practice set 2: Count square units to find area

Problem 2A
• Current
What is the area of the shape? Each square in the grid is a 1, times, 1 unit square.
A figure with 4 rows and 4 columns of 11 unit squares connected together on a grid. The top 2 rows each have 4 unit squares. The third row has 2 unit squares. The bottom row has 1 unit square.
square units

### Practice set 3: Challenge items

Problem 3A
• Current
This cat and bird picture has an area of 56 square centimeters. The height of the picture is 7 centimeters.
What is the width of the picture?
centimeters
A rectangular picture of a cat and a bird. The left side of the picture is labeled 7 centimeters and the top side of the picture is labeled width.

## Want to join the conversation?

• How do you figure out square feet? I need to calculate the area of a back splash so i can purchase wall tiles.
• for tiles times the length by the width and you get the area
• Pls upvote this sentence (Im going for a badge)
• how do you find area of a 3D shape? is it multiplying 2D shapes? why does time pass in different time zones? how does an earthquake cause a tsunami? also, force can move things right? how can a smaller amount of force move a big object?
• time passes in different time zones cause of the way the earth is facing the sun
• If a shape is uneven, how can we work out the area?
• Try to break the shape into simpler shapes - ones that have areas that are easy to calculate. Calculate the area of each smaller shape, then add them all together to get the area of the whole shape.
(This is what they did up above when they had us count squares to figure out the area of the big shape.)

Each square is 1x1, so the area of each square is one.
(First step: calculating the area of the smaller shapes.)

Then when we counted all the squares, the total number of squares was also the area of the shape.
(Second step: add together all the areas of the smaller shapes.)

Hope this helps!
• this is a good practice but a bit tricky
• whats the first answer for the frist one