We can use this formula when we are given two sides and the included angle.

Finding the area of a triangle? Know the length of the base and the height? Then just take those values and plug them into the formula for the area of a triangle and solve! This tutorial shows you how.

When we know the base and height it is easy.

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There's also a formula to find the area of any triangle when we know the lengths of all three of its sides.

Did you know that the formula for the area of a triangle can be found by using the formula for the area of a parallelogram? In this tutorial, you'll see how it's done! Take a look!

The angle between fence AB and fence BC is 123ยบ.

You can't do algebra without working with variables, but variables can be confusing. If you've ever wondered what variables are, then this tutorial is for you!

To find the area of a rectangle, multiply the length times the width! This tutorial will show you how to find the area of a rectangle. Check it out!

Again, you must decide which of the 3 bases to use. Just remember that base and height are perpendicular. Therefore, the base is '22' since it is perpendicular to the height of 26.8

What is the area of the triangle pictured below?

What is the area of the triangle in the following picture?

There are several ways to find the area of a triangle.

To find the area of the triangle on the left, substitute the base and the height into the formula for area.

In the right area? Find out with this activity.

Find the area of each triangle below. Round each answer to the nearest tenth of a unit.

First of all we must decide what we know.

So to find the area of a triangle, multiply the base by the perpendicular height and divide by two. The formula is:

When we know two sides and the included angle (SAS), there is another formula (in fact three equivalent formulas) we can use.

Depending on which sides and angles we know, the formula can be written in three ways:

Remember to show all your working. It is easy to make a mistake when using your calculator, and you will not get any marks for a wrong answer.

The picture below shows you that the height can actually extend outside of the triangle. So technically the height does not necessarily intersect with the base.

Like the last problem, you must decide which of the 3 bases to use. Just remember that base and height are perpendicular. Therefore, the base is '4' since it is perpendicular to the height of 17.7

The area of a triangle is always half the product of the height and base.

Plugging variables into an expression is essential for solving many algebra problems. See how to plug in variable values by watching this tutorial.

They are really the same formula, just with the sides and angle changed.

By changing the labels on the triangle we can also get:

### How to find the area of a triangle

The length of the fence AB is 150 m. The length of the fence BC is 231 m.

Well, we know that we can find an area when we know a base and height:

This can be found on the Heron's Formula page.

Though the most common way to find the area of a triangle is to multiply the base and height and to divide the result by two, there are a number of other ways to find the area of a triangle depending on what dimensions you are given. There are other formulas for finding the area of a triangle depending on whether you know the length of the three sides, the length of one side of an equilateral triangle, or the length of two sides and their included angle.

To find the area of a triangle, use the following formula

First of all we must decide which lengths and angles we know:

Just think "abc": Area = ½ a b sin C

Now to take a different angle on revision with this activity!

This problems involves 1 small twist. You must decide which of the 3 bases to use. Just remember that base and height are perpendicular. Therefore, the base is '11' since it is perpendicular to the height of 13.4.

Multiplying a whole number and a fraction can be confusing, but this tutorial helps to sort things out. Check it out!

If you multiply the base by the perpendicular height, you get the area of a rectangle. The area of the triangle is half the area of the rectangle.

This problems involves 1 small twist. You must decide which of the 3 bases to use. Just remember that base and height are perpendicular. Therefore, the base is '12' since it is perpendicular to the height of 5.9

This lesson is by Gisele Glosser. You can find me on Google.