# The formula for the perimeter of a triangle

# O = a + b +c

Legend:

## O – perimeter of a triangle

## a – the length of the base of the triangle

## b – the length of the side of the triangle

## c – the length of the side of the triangle

Sample task:

Calculate the perimeter of the triangle with the base a = 10 cm, side b = 9 cm and side c = 8 cm

#### O = a + b +c

#### O = 10cm + 9cm +8 cm

#### O = 27 cm

The perimeter of a triangle with a base a = 10 cm, side b = 9 cm and side c = 8 cm, is 27cm.

# The formula for the perimeter of an equilateral triangle

# O = a + b +c

calculating the perimeter of an equilateral triangle, which has all sides of equal length. If we know the side length of an equilateral triangle, we can write it down, that his **circuit** is equal: