Perimeter of a sector

The perimeter is the distance all around the outside of a shape. We can find the perimeter of a sector using what we know about finding the length of an arc.

A sector is formed between two radii and an arc. To find the perimeter, we need to add these values together.

\text{Perimeter = Arc length + 2r}

A sector with a radius of 45 cm and arc length 27.5 cm.

Here, we are given the arc length and the radius.

Substituting these values, we get:

\text{Perimeter = 27.5 + (2 \times 45)}

\text{= 27.5 + 90}

\text{= 117.5 cm}


Find the perimeter of this sector.

A sector with a radius of 10 cm and arc length 15 cm.

\text{Perimeter = 15 + (2 \times 10)}

\text{= 15 + 20}

\text{= 35 cm}