## AREA OF RHOMBUS

The area of a rhombus is equal to one half the product of the lengths of the diagonals. Let d1 and d2 be the lengths of diagonals of a rhombus.

Example 1 :

If the lengths of the diagonals of a rhombus are  16 cm and 30 cm, find its area.

Solution :

Formula for area of a rhombus :

1/2 ⋅ (d1d2)

Substitute 16 for d1 and 30 for d2.

=   1/2 ⋅ (16 ⋅ 30)

=   8 ⋅ 30

=  240 cm2

So, area of the rhombus is 240 square cm.

Example 2 :

Find the area of the rhombus shown below. Solution :

In the rhombus shown above,

d1  =  5 + 5  =  10 units

d2  =  4 + 4  =  8 units

Formula for area of a rhombus :

=   1/2 ⋅ (d1d2)

Substitute 10 for d1 and 8 for d2.

=   1/2 ⋅ (10 ⋅ 8)

=   5 ⋅ 8

=  40

So, area of the rhombus is 40 square units.

Example 3 :

Area of a rhombus is 192 square cm. If the length of one of the diagonals is 16 cm, find the length of the other diagonal.

Solution :

Area of the rhombus  =  192 cm2

1/2 ⋅ (d1d2)  =  192

Substitute 16 for d1.

1/2 ⋅ (16  d2)  =  192

d2  =  192

Divide each side by 8.

d2  =  24 cm

So, the length of the other diagonal is 24 cm.

Example 4 :

Area of a rhombus is 120 square units. If the lengths of the diagonals are 10 units and (7x + 3) units, then find the value of x.

Solution :

Area of the rhombus  =  120 cm2

1/2 ⋅ (d1d2)  =  120

Substitute 10 for d1 and (7x + 3) for d2

1/2 ⋅ [10(7x + 3)]  =  120

5(7x + 3)  =  120

Divide each side by 5.

7x + 3  =  24

Subtract 3 from each side.

7x  =  21

Divide each side by 7.

x  =  3

Example 5 :

Area of the rhombus shown below is 48 square inches. What is the value of x ? Solution :

In the rhombus shown above,

d1  =  8 + 8  =  16 units

d2  =  x + x  =  2x units

Given : Area of the rhombus is 48 square inches.

Then,

1/2 ⋅ (d1d2)  =  48

Substitute 16 for d1 and 2x for d2.

1/2  (16 ⋅ 2x)  =  48

⋅ 2x  =  48

16x  =  48

Divide each side by 16.

x  =  3

Example 6 :

Find the area of the rhombus shown below. Solution :

Measure the lengths of the diagonals AC and BD. The lengths of the diagonals are  4 units and 2 units.

Formula for area of a rhombus :

=   1/2 ⋅ (d1d2)

Substitute 4 for d1 and 2 for d2.

=   1/2 ⋅ (4 ⋅ 2)

=   2 ⋅ 2

=  4

So, area of the rhombus is 4 square units.

Example 7 :

Find the area of the rhombus having each side equal to 17 cm and one of its diagonals equal to 16 cm.

Solution :

Let A, B, C and D be the vertices of the rhombus.

The diagonals of a rhombus will be perpendicular and they will bisect each other.

Then, we have In the above rhombus, consider the right angled triangle BDE.

By Pythagorean Theorem,

BD2  =  BE2 + DE2

172  =  BE2 + 82

289  =  BE2 + 64

Subtract 64 from each side.

225  =  BE2

152  =  BE2

15  =  BE

Then,

EC  =  15

Length of the diagonal BC :

BC  =  BE + EC

BC  =  15 + 15

BC  =  30 units

So, the lengths of the diagonals are 16 units and 30 units.

Formula for area of a rhombus :

=   1/2 ⋅ (d1d2)

Substitute 16 for d1 and 30 for d2.

=   1/2 ⋅ (16 ⋅ 30)

=   8 ⋅ 30

=  240

So, area of the rhombus is 240 square units.

Kindly mail your feedback to v4formath@gmail.com

## Recent Articles 1. ### Fractions Decimals and Percentages Word Problems

Feb 02, 23 07:46 AM

Fractions Decimals and Percentages Word Problems

2. ### Worksheet on Word Problems on Linear Equation in One Variable

Feb 02, 23 12:48 AM

Worksheet on Word Problems on Linear Equation in One Variable