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Perimeter of a closed figure is the distance around it, whereas area is the region enclosed by closed figure.

Perimeter of a regular polygon = number of sides x length of one side.

**Area and perimeter of a rectangle**

The perimeter of a rectangle is twice the sum of the lengths of its adjacent sides.

Perimeter of a rectangle of length 'l' units and breadth 'b' units = 2(l + b).

The area of a rectangle is the product of its length and breadth.

Area of a rectangle of length 'l' units and breadth 'b' units = l Ã— b.

The perimeter of rectangle ABCD = 2(AB + BC).

Area of rectangle ABCD = AB x BC.

Each diagonal of a rectangle divides it into two triangles that are equal in area.

**Area and perimeter of a square**

The perimeter of a square with side s units is the four times the length of its side.

Perimeter of a square with side s units = 4 Ã— s

The area of a square with side s is is equal to side multiplied by side.

Area of a square with side s units = s Ã— s

The perimeter of square ABCD = 4AB or 4BC or 4CD or 4DA.

Area of square ABCD = AB^{2} or BC^{2} or CD^{2} or DA^{2}.

The diagonals of a square divide it into four triangles that are equal in area. A rectangle and a square having the same perimeter need not have the same area. If the perimeter of a figure increases it is not necessary that its area also increases.

**Area and perimeter of a triangle**

The perimeter of a triangle is the sum of the lengths of its sides.

Perimeter of a triangle with sides a, b and c = (a + b + c).

The area of a triangle is the space enclosed by its three sides.

Area of a triangle is half of the product of its base and the corresponding altitude.

Area of a triangle with b as the base and h as the altitude = $\frac{\text{1}}{\text{2}}$ Ã— bh.

Triangles equal in area need not be congruent, but all congruent triangles are equal in area.

**Area and perimeter of a parallelogram**

The perimeter of a parallelogram is twice the sum of the lengths of the adjacent sides.

The area of a parallelogram is the product of its base and the corresponding altitude.

Area of a parallelogram with b as the base and h as the altitude = b Ã— h.

Any side of a parallelogram can be considered as the base. The perpendicular drawn on that side from the opposite vertex is known as the height (altitude).

The perimeter of parallelogram ABCD = 2(AB + BC)

Area of parallelogram ABCD = (AB x DE) or (AD x BF).

A parallelogram in which the adjacent sides are equal is called a rhombus.

The perimeter and area of a rhombus can be calculated using the same formulae as that for a parallelogram.

**Conversion of units**

1cm = 10 mm

1 cm^{2} = 100 mm^{2}

1 m^{2} = 10000 cm^{2}

1 hectare = 10,000 m^{2}

Perimeter of a closed figure is the distance around it, whereas area is the region enclosed by closed figure.

Perimeter of a regular polygon = number of sides x length of one side.

**Area and perimeter of a rectangle**

The perimeter of a rectangle is twice the sum of the lengths of its adjacent sides.

Perimeter of a rectangle of length 'l' units and breadth 'b' units = 2(l + b).

The area of a rectangle is the product of its length and breadth.

Area of a rectangle of length 'l' units and breadth 'b' units = l Ã— b.

The perimeter of rectangle ABCD = 2(AB + BC).

Area of rectangle ABCD = AB x BC.

Each diagonal of a rectangle divides it into two triangles that are equal in area.

**Area and perimeter of a square**

The perimeter of a square with side s units is the four times the length of its side.

Perimeter of a square with side s units = 4 Ã— s

The area of a square with side s is is equal to side multiplied by side.

Area of a square with side s units = s Ã— s

The perimeter of square ABCD = 4AB or 4BC or 4CD or 4DA.

Area of square ABCD = AB^{2} or BC^{2} or CD^{2} or DA^{2}.

The diagonals of a square divide it into four triangles that are equal in area. A rectangle and a square having the same perimeter need not have the same area. If the perimeter of a figure increases it is not necessary that its area also increases.

**Area and perimeter of a triangle**

The perimeter of a triangle is the sum of the lengths of its sides.

Perimeter of a triangle with sides a, b and c = (a + b + c).

The area of a triangle is the space enclosed by its three sides.

Area of a triangle is half of the product of its base and the corresponding altitude.

Area of a triangle with b as the base and h as the altitude = $\frac{\text{1}}{\text{2}}$ Ã— bh.

Triangles equal in area need not be congruent, but all congruent triangles are equal in area.

**Area and perimeter of a parallelogram**

The perimeter of a parallelogram is twice the sum of the lengths of the adjacent sides.

The area of a parallelogram is the product of its base and the corresponding altitude.

Area of a parallelogram with b as the base and h as the altitude = b Ã— h.

Any side of a parallelogram can be considered as the base. The perpendicular drawn on that side from the opposite vertex is known as the height (altitude).

The perimeter of parallelogram ABCD = 2(AB + BC)

Area of parallelogram ABCD = (AB x DE) or (AD x BF).

A parallelogram in which the adjacent sides are equal is called a rhombus.

The perimeter and area of a rhombus can be calculated using the same formulae as that for a parallelogram.

**Conversion of units**

1cm = 10 mm

1 cm^{2} = 100 mm^{2}

1 m^{2} = 10000 cm^{2}

1 hectare = 10,000 m^{2}