Examples with solutions for Area of a Rectangle: Worded problems

Exercise #1


What is the length of the second side in a rectangle, given that the sum of the 2 opposite sides is 14 cm and the area of the rectangle is 21 cm²?

Video Solution

Step-by-Step Solution

If we are given that two opposite sides of the rectangle sum to 14

and in a rectangle, each pair of opposite sides are equal to each other, we will calculate the size of each one as follows:

14:2=7 14:2=7

We will call the other two opposite sides y and find the unknown as follows:

7×y=21 7\times y=21

We will divide both sides by 7 and get:

y=3 y=3

Answer

3

Exercise #2

The area of a rectangle is 256 cm².

One side is 4 times longer than the other.

What are the dimensions of the rectangle?

Video Solution

Step-by-Step Solution

To find the area of the rectangle, we multiply the length by the width.

According to the data in the statement, one side will be equal to X and the other side will be equal to 4X

Now we replace the existing data:

S=x×4x S=x\times4x

256=4x2 256=4x^2

We divide the two sections by 4:

64=x2 64=x^2

We extract the square root:

x=64=8 x=\sqrt{64}=8

If we said that one side is equal to x and the other side is equal to 4x and we know that x=8

From here we can conclude that the sides of the rectangle are equal:

8,8×4=8,32 8,8\times4=8,32

Answer

8 x 32

Exercise #3

Joseph is building a pool.

He buys tiles with sides measuring 10 cm by 5 cm.

The size of Joseph's pool is 850 cm².

How many tiles does Joseph need?

Video Solution

Step-by-Step Solution

First, let's calculate the area of the tile by multiplying length and width:

10×5=50 10\times5=50

Now let's calculate how many tiles fit in the given pool area - 850 cm²:

850:50=17 850:50=17

Therefore, Yossi needs 17 tiles

Answer

17 17

Exercise #4

The area of the square whose side length is 4 cm is
equal to the area of the rectangle whose length of one of its sides is 1 cm.

What is the perimeter of the rectangle?

Video Solution

Step-by-Step Solution

After squaring all sides, we can calculate the area as follows:

42=16 4^2=16

Since we are given that the area of the square equals the area of the rectangle , we will write an equation with an unknown since we are only given one side length of the parallelogram:

16=1×x 16=1\times x

x=16 x=16

In other words, we now know that the length and width of the rectangle are 16 and 1, and we can calculate the perimeter of the rectangle as follows:

1+16+1+16=32+2=34 1+16+1+16=32+2=34

Answer

34

Exercise #5

Gerard plans to paint a fence 7X meters high and 30X+4 meters long.

Gerardo paints at a rate of 7 m² per half an hour.

Choose the expression that represents the time it takes for Gerardo to paint one side of the fence.

30X+430X+430X+47X7X7X

Video Solution

Step-by-Step Solution

In order to solve the exercise, we first need to know the total area of the fence.

Let's remember that the area of a rectangle equals length times width.

Let's write the exercise according to the given data:

7x×(30x+4) 7x\times(30x+4)

We'll use the distributive property to solve the exercise. That means we'll multiply 7x by each term in the parentheses:

(7x×30x)+(7x×4)= (7x\times30x)+(7x\times4)=

Let's solve each term in the parentheses and we'll get:

210x2+28x 210x^2+28x

Now to calculate the painting time, we'll use the formula:

7m212hr=14m2hr \frac{7m^2}{\frac{1}{2}hr}=14\frac{m^2}{hr}

The time will be equal to the area divided by the work rate, meaning:

210x2+28x14 \frac{210x^2+28x}{14}

Let's separate the exercise into addition between fractions:

210x214+28x14= \frac{210x^2}{14}+\frac{28x}{14}=

We'll reduce by 14 and get:

15x2+2x 15x^2+2x

And this is Isaac's work time.

Answer

15x2+2x 15x^2+2x hours

Exercise #6

The length of the side of the square x+1 x+1 cm

(x>3)

We extend one side by 1 cm and shorten an adjacent side by 1 cm, and we obtain a rectangle.

What is the area of the rectangle?

Video Solution

Answer

x2+2x x^2+2x

Exercise #7

The length of the square is equal to x x cm

(x>1) We extend one side by 3 cm and shorten an adjacent side by 1 cm and we obtain a rectangle,

What is the length of the side of the given square if it is known that the two areas are equal?

Video Solution

Answer

x=32cm x=\frac{3}{2}cm

Exercise #8

The length of the side of a square is X cm

(x>3)

Extend one side by 3 cm and shorten an adjacent side by 3 cm to obtain a rectangle.

Express the area of the rectangle using x.

Video Solution

Answer

x29(cm2) x^2-9\left(\operatorname{cm}²\right)

Exercise #9

The side length of a square is X cm

(x>3)

We extend one side by 3 cm and shorten an adjacent side by 3 cm, and we get a rectangle.

Which shape has a larger area?

Video Solution

Answer

The square