QUICK LINKS


Introduction

QUICK LINKS


Introduction

INTRO
When we’re asked to find the area of a triangle, what we’re looking for is the amount of space inside the sides of our triangle.
The formula is pretty straightforward, but correctly identifying the base and the height of the triangle can sometimes be tricky. That’s why we like to imagine triangles as mountains!

Type of Triangle:

We can imagine the triangle as a mountain where the base is flat (), and the height is a vertical line that connects the base to the peak ().
Sometimes, we may need to rotate our triangle in order for it look like a mountain:Check out our
Calculator
or explore our
Lesson
and
Practice
sections to learn more about how to find the area of triangles and test your understanding.

You can also use the Quick Links menu on the left to jump to a section of your choice.

You can also use the Quick Links dropdown above to jump to a section of your choice.

CALCULATOR

Area of Triangles Calculator

What does your triangle look like?

Step 1. Identify the base and height of the triangle.

Imagine the triangle is a mountain. The base must be flat and the height connects the base of the mountain to the peak.

Step 2. Multiply the base by the height.

Step 3. Divide by 2.

So, the area of the triangle is .
KEY STEPS

How to Find the Area of a Triangle

Step 1. Identify the base and height of the triangle.

Imagine the triangle is a mountain. The base must be flat and the height connects the base of the mountain to the peak.

Step 2. Multiply the base by the height.

Step 3. Divide by 2.

We divide by 2 because the area of a right triangle is equal to ½ the area of a rectanglemade up of two right triangles with the same base and height.
LESSON
Right Triangles

Right Triangles

The area of a right triangle is equal to the area of a rectangle made up of two right triangles with the same base and height:

Let's do some practice problems!

EXAMPLE 1

We'll start with this triangle:

EXAMPLE 2

Nice work! Now, you might have noticed that right triangles are special because we can choose to make either of the two perpendicular sides of the triangle the base and height. Let’s try an example where we can see this in practice!
Awesome! Expand the
Practice
below to try some more problems or expand the next
Lesson
to explore what we do when we're dealing with acute triangles.
PRACTICE
Right Triangles

Practice: Area of Right Triangles

Question 1 of 3: Find the area of this triangle ⬇️

Step 1. Identify the base and height of the triangle.

Imagine the triangle is a mountain. The base must be flat and the height connects the base of the mountain to the peak.

Step 2. Multiply the base by the height.


Step 3. Divide by 2.

Nice work! Our answer is .

LESSON
Acute Triangles

Acute Triangles

The area of an acute triangle is equal to the area of a parallelogram made up of two acute triangles with the same base and height:

When it comes to finding the area of an acute triangle, the height will be shown inside the triangle as a straight or dotted line connecting the base to the peak:Let's try some examples 🔥.

EXAMPLE 1

We'll start with this triangle:

EXAMPLE 2

Amazing job! Now try another one - and don't get distracted by all the different side lengths 🙈.
Awesome! Expand the
Practice
below to try some more problems or expand the next
Lesson
to explore what we do when we're dealing with obtuse triangles.
PRACTICE
Acute Triangles

Practice: Area of Acute Triangles

Question 1 of 3: Find the area of this triangle ⬇️

Step 1. Identify the base and height of the triangle.

Imagine the triangle is a mountain. The base must be flat and the height connects the base of the mountain to the peak.

Step 2. Multiply the base by the height.


Step 3. Divide by 2.

Nice work! Our answer is .

LESSON
Obtuse Triangles

Obtuse Triangles

The area of an obtuse triangle is equal to the area of a parallelogram made up of two obtuse triangles with the same base and height:

When it comes to finding the area of an obtuse triangle, the height will be show outside the triangle, since it needs to be a vertical line connecting the base to the peak:Let's try some examples 🔥🔥.

EXAMPLE 1

Start with this one:

EXAMPLE 2

Wow nice job! Try one more:
Awesome! If you’d like to practice additional problems with obtuse triangles, expand the
Practice
below before closing out this lesson! ⚡
PRACTICE
Obtuse Triangles

Practice: Area of Obtuse Triangles

Question 1 of 3: Find the area of this triangle ⬇️

Step 1. Identify the base and height of the triangle.

Imagine the triangle is a mountain. The base must be flat and the height connects the base of the mountain to the peak.

Step 2. Multiply the base by the height.


Step 3. Divide by 2.

Nice work! Our answer is .

CONCLUSION
Amazing work, look at you go! Thanks for checking out this lesson ☺️🙏. Where to next?
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