### Types of parallelograms

##### Perimeter of a square

What do we need to know about the square? A square has four equal sides!

Formula: P = a + a + a + a

or

**P = 4.a **

The task from the example:

P = 4.2

P = 16 sm

##### Perimeter of a rectangle

What do we need to know about the rectangle? A rectangle consists of two opposite equal sides!

Formula: P = a + a + b + b

or

**P = 2.a + 2.b **

The task from the example:

P = 2.4 + 2.2

P = 12 sm

### Types of triangles

##### Perimeter of an equilateral triangle

What should we know about this kind of triangle triangle? An equilateral triangle has three equal sides!

Formula: P = a + a + a

or

**P = 3.a **

The task from the example:

P = 3.2

P = 6 sm

##### Perimeter of an isosceles triangle

What should we know about this kind of triangle triangle? An isosceles triangle has two equal sides!

Formula: P = a + b + b

or

**P = a + 2.b **

The task from the example:

P = 2 + 2.3

P = 8 sm

##### Perimeter of a scalene triangle

What should we know about this kind of triangle triangle? Scalene triangle has no equal sides!

Formula:

**P = a + b + c **

The task from the example:

P = 2 + 3 + 4

P = 9 sm