Examples with solutions for Perimeter of a Parallelogram: Using variables

Exercise #1

The parallelogram ABCD has a perimeter equal to 80 cm.

Calculate X.

XXX2X2X2XAAABBBCCCDDD

Video Solution

Step-by-Step Solution

Since in a parallelogram each pair of opposite sides are equal and parallel:

BC=AD=2x BC=AD=2x

AB=CD=x AB=CD=x

Now let's substitute the known data into the formula for calculating the perimeter:

80=2x×2+2×x 80=2x\times2+2\times x

80=4x+2x 80=4x+2x

80=6x 80=6x

Let's divide both terms by 6:

806=6x6 \frac{80}{6}=\frac{6x}{6}

806=x \frac{80}{6}=x

Let's simplify the fraction by 2

403=x \frac{40}{3}=x

Answer

x=403 x=\frac{40}{3}

Exercise #2

The longest sides of a parallelogram are X cm long and are four times longer than the shorter sides.

AAABBBDDDCCC

Express the perimeter of the parallelogram in terms of X.

Video Solution

Step-by-Step Solution

In a parallelogram, each pair of opposite sides are equal and parallel: AB = CD and AC = BD.

Given that the length of one side is 4 times greater than the other side equal to X, we know that:

AB=CD=4AC=4BD AB=CD=4AC=4BD

Now we replace the data in this equation with out own (assuming that AB = CD = X):

x=x=4AC=4BD x=x=4AC=4BD

We divide by 4:

x4=x4=AC=BD \frac{x}{4}=\frac{x}{4}=AC=BD

Now we calculate the perimeter of the parallelogram and express both AC and BD using X:

P=x+x4+x+x4 P=x+\frac{x}{4}+x+\frac{x}{4}

P=2x+x4+x4=212x P=2x+\frac{x}{4}+\frac{x}{4}=2\frac{1}{2}x

Answer

2.5X cm

Exercise #3

Look at the parallelogram shown below.

AB = 6

AC = X

The perimeter of the parallelogram is 20.

AAABBBDDDCCC6X

Find X.

Video Solution

Step-by-Step Solution

As is true for a parallelogram each pair of opposite sides are equal:

AB=CD=6,AC=BD=x AB=CD=6,AC=BD=x

Calculate X according to the given perimeter:

20=6+6+x+x 20=6+6+x+x

20=12+2x 20=12+2x

2012=2x 20-12=2x

8=2x 8=2x

x=4 x=4

Answer

4

Exercise #4

A parallelogram has one side that is 2 times longer than the other. The length of the smaller side is X.

AAABBBDDDCCC

Express the circumference of the parallelogram in terms of X.

Video Solution

Step-by-Step Solution

As is true of a parallelogram each pair of opposite sides are equal to one another

AB=CD,AC=BD AB=CD,AC=BD

Given that AB > AC

Let's call AC by the name X and therefore:

AB=2AC=2×x=2x AB=2AC=2\times x=2x

Now we know that:

AB=CD=2x,AC=BD=x AB=CD=2x,AC=BD=x

The perimeter is equal to the sum of all the sides together:

2x+x+2x+x=6x 2x+x+2x+x=6x

Answer

4X+4

Exercise #5

ABCD is a parallelogram whose perimeter is equal to 24 cm.

The side of the parallelogram is two times greater than the adjacent side (AB>AD).

CE is the height of the side AB

The area of the parallelogram is 24 cm².

Find the height of CE

AAABBBCCCDDDEEE

Video Solution

Step-by-Step Solution

The perimeter of the parallelogram is calculated as follows:

SABCD=AB+BC+CD+DA S_{ABCD}=AB+BC+CD+DA Since ABCD is a parallelogram, each pair of opposite sides is equal, and therefore, AB=DC and AD=BC

According to the figure that the side of the parallelogram is 2 times larger than the side adjacent to it, it can be argued thatAB=DC=2BC AB=DC=2BC

We inut the data we know in the formula to calculate the perimeter:

PABCD=2BC+BC+2BC+BC P_{ABCD}=2BC+BC+2BC+BC

We replace the given perimeter in the formula and add up all the BC coefficients accordingly:

24=6BC 24=6BC

We divide the two sections by 6

24:6=6BC:6 24:6=6BC:6

BC=4 BC=4

We know thatAB=DC=2BC AB=DC=2BC We replace the data we obtained (BC=4)

AB=DC=2×4=8 AB=DC=2\times4=8

As ABCD is a parallelogram, then all pairs of opposite sides are equal, therefore BC=AD=4

To find EC we use the formula:AABCD=AB×EC A_{ABCD}=AB\times EC

We replace the existing data:

24=8×EC 24=8\times EC

We divide the two sections by 824:8=8EC:8 24:8=8EC:8

3=EC 3=EC

Answer

3 cm

Exercise #6

ABCD is a parallelogram whose perimeter is equal to 22 cm.

AC=4 height of the parallelogram for side CD is 3 cm

Calculate the area of the parallelogram

444AAABBBDDDCCC

Video Solution

Answer

21 cm².

Exercise #7

Calculate the perimeter of the parallelogram ABCD.

AB is parallel to CD.

XXX101010AAABBBCCCDDD

Video Solution

Answer

2x+20 2x+20

Exercise #8

Given a parallelogram in which the length of one side is 2 times the length of the other side and given that the length of the larger side is 0.5X:

AAABBBDDDCCC

Express by X the perimeter of the parallelogram.

Video Solution

Answer

1.5X

Exercise #9

Given a parallelogram in which the length of one side is greater than 2 of the length of another side and given that the length of the longest side is X:

AAABBBDDDCCC

Express by X the perimeter of the parallelogram.

Video Solution

Answer

3X

Exercise #10

Below is a parallelogram.

AB = 4

AC = X-2

The perimeter of the parallelogram is 10.

AAABBBDDDCCC4X-2

Calculate X.

Video Solution

Answer

3

Exercise #11

Shown below is a parallelogram.

AB = 7

AC = 0.5X

The perimeter of the parallelogram is 21.

AAABBBDDDCCC70.5X

Calculate side AC.

Video Solution

Answer

3.5

Exercise #12

Look at the parallelogram below.

AB = 10

AC = X

The perimeter of the parallelogram is 30.

AAABBBDDDCCC10X

Calculate X.

Video Solution

Answer

5

Exercise #13

A parallelogram is shown below.

AB = 5

AC = 2X

The perimeter of the parallelogram is 20.

AAABBBDDDCCC52X

Calculate the length of side AC.

Video Solution

Answer

5

Exercise #14

A parallelogram is shown below.

AB = 8

AC = X+2

The perimeter of the parallelogram is 30.

AAABBBDDDCCC8X+2

Calculate X.

Video Solution

Answer

5

Exercise #15

Given a parallelogram where the length of one side is greater by 4 than the length of another side and given that the length of the smaller side is X:

AAABBBDDDCCC

Express by X the perimeter of the parallelogram.

Video Solution

Answer

4X+8

Exercise #16

Given a parallelogram in which the length of one side is 2 greater than the length of another side and given that the length of the larger side is 2X:

AAABBBDDDCCC

Express by X the perimeter of the parallelogram.

Video Solution

Answer

6X

Exercise #17

How long is side BC given that the perimeter of the parallelogram is 30 cm?

CD=2x CD=2x

2x2x2xAAABBBCCCDDD

Video Solution

Answer

152x 15-2x

Exercise #18

ABCD is a parallelogram whose perimeter is equal to 22 cm.

Side AB is smaller by 5 than side AD

The height of the parallelogram for the side AD is 2 cm

What is the area of the parallelogram?

AAABBBCCCDDD

Video Solution

Answer

16 cm²