Area of a Triangle

​Area of a Triangle

What is a triangle

• A two-dimensional polygon with three edges and three vertices.

• It is one of the basic shapes in geometry.

• The sum of the internal angles equal 180^o.

Area of Triangles

How can you use the formula for the area of a parallelogram to find the area of a triangle?

The diagonal of a parallelogram divides it into two identical triangles.

The area of one triangle must be half the area of a parallelogram that has the same base and height.

Finding the Area of a Triangle

Given:

the base = 30 and the height = 21

Find:

area of the triangle

Area_Δ = 1/2 * b * h

Area_Δ = 1/2 * 30 * 21 = 315 m²

Finding the Area of a Triangle

1) Identify what has been given and what you are looking to find.

Given: b = 30 km and h = 20 km

2) Write down the formula.

A_Δ = 1/2 x b x h

3) Solve (using calculator if needed)

A_Δ = 1/2 x 30km x 20km = 300 km²

Finding the Area of a Triangle

1) Identify what has been given and what you are looking to find.

Given: b = _____ and h = _____

2) Write down the formula.

A_Δ =

3) Solve (using calculator if needed)

A_Δ =

Area of a Triangle - UR Turn

1) Identify what has been given and what you are looking to find.

Given: b = _____ and h = _____

2) Write down the formula.

A_Δ =

3) Solve (using calculator if needed)

A_Δ =

Area of a Triangle - UR Turn

Find the area of triangle A

A_Δ =

Find the area of triangle B

A_Δ =

WHAT did you get ?

Answers in the CHAT ! ! !