Surface Area of a Triangle with Formula

Surface Area of Triangle Formula

The surface area of a triangle formula is: 1/2 × base × height.

The formula can also be expressed as:

Area of a triangle formula

In the formula above, A is the area of the triangle, b is the base, and h is the height.

Area of a Triangle – Quiz


[WpProQuiz 35]

The examples that follow illustrate how to use the formula.

Surface Area of a Triangle Formula – Example

In exam questions on triangles, you may see illustrations of triangles.

Alternatively, the facts and measurements of the figure may be given in narrative form, without an illustration.

For example, you might see a figure like the one below:

Area of a triangle formula 7 units

On the other hand, the question may be presented in narrative form.

Example: What is the area of a triangle with a height of 7 units and a base of 5 units?

Answer: The answer to the question is an area of 17.5 square units.

To solve the problem, we need to use the area of a triangle formula provided above.

Area of a triangle formula = 1/2 × base × height

Then substitute the values stated in the question.

1/2 × 5 × 7 =

1/2 × 35 =

17.5

Triangles and Other Shapes

Exam questions may cover triangles that lie inside other shapes.


These types of exam questions will often show a triangle or triangles inside a rectangle.

Triangles can also be added to the sides of a rectangle to form a trapezoid.

Two congruent triangles can be joined at the base to form a parallelogram.

Look at the illustration below:

Area of a triangle formula parallelogram

So, you might also see questions on parallelograms and trapezoids on the exam.

You may also want to try our other free geometry questions.

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