Area of A Triangle: Its Formula and Examples
by Daisy, May 10 2023
Have you ever tried to cover a triangle-shaped pizza with an extra layer of cheese? Or maybe you've tried to find out how much carpet you need for a room that's shaped like a triangle? In order to do this, you need to know the size of the triangle's surface - this is called the area of the triangle!
What's the Area of a Triangle?
The area of a triangle is the amount of space inside it, like how much space is covered by the pizza or how much carpet is needed for the floor. To find the area of a triangle, we need to know two things: its base (the bottom) and its height (how tall it is).
We can use a special formula to figure out the area of any type of triangle:
Area = 1/2 × base × height
We can also write it like this: A = 1/2 × b × h
Think of it like building a sandcastle on the beach - if you know the length of the base of the triangle (the bottom of the castle) and how high you want to build it (the height), you can use the formula to figure out how much sand you need to fill the space inside the triangle!
So, to find the area of a triangle, just remember the formula - half times base times height!
An Example of Area of a Triangle
Imagine you have a slice of pizza that is shaped like a triangle. The area of the triangle is like how much space it takes up on a 2-dimensional flat surface, just like a puzzle piece fitting into a puzzle.
To find the area of a triangle, we need to know two things: the height and the base. The height is how tall the triangle is, from the very top down to the base. The base is how long the bottom side of the triangle is.
To make it even easier, let's pretend you have a toy triangle. You can use a ruler to measure how tall the triangle is and how long the base is. Then, you can use a special formula to find the area of the triangle! The formula is:
Area of triangle = (base x height) ÷ 2
That means you multiply the base and the height together, and then divide by 2. It's like cutting the pizza slice in half to make two smaller triangles. Then you can add up the areas of each of those triangles to get the total area of the whole slice of pizza!
So, the area of a triangle is like how much space it takes up on a flat surface. We can find the area by using the formula (base x height) ÷ 2. It's like cutting a pizza slice in half to make two smaller triangles, and then adding up their areas to find the total area of the whole slice!
Calculate the Area of Triangle
There are different ways to find the area of a triangle depending on what information we know about it. Let me break it down for you in a way that's easy to understand.
When we know the length of all three sides of a triangle, we can use something called Heron's Formula. It might look a little scary, but it's actually pretty simple. We just need to find something called the semi-perimeter, which is just half the sum of all three sides. Then, we use that in the formula:
Area = √(s(s-a)(s-b)(s-c))
Here, 'a', 'b', and 'c' are the lengths of the sides, and 's' is the semi-perimeter we just calculated. This formula helps us find the area of a triangle even if the sides are not equal.
When we have a right-angled triangle, we can use a different formula. In this case, the base and height of the triangle are easy to find because the height is just one of the sides. We can use the Pythagorean Theorem to find the height if we know the other two sides. Then, we just use the formula:
Area = 1/2 x base x height
When we have an equilateral triangle, which means all sides are equal, we have a special formula just for that. We just need to know the length of one side, which we'll call 's', and then use the formula:
Area = (sqrt(3)/4) x s^2
Finally, if we have the coordinates of the three vertices of a triangle on a graph, we can find the area by using the formula for a right-angled triangle if the triangle is a right-angled triangle, and using Heron's Formula for any other triangle. We just need to calculate the length of the sides using the distance formula, and then find the semi-perimeter if we're using Heron's Formula.
Conclusion
Imagine you have a triangular piece of land. The area of this piece of land is the space within the three sides of the triangle. The area of a triangle depends on the length of its sides and the angles they form. Different triangles can have different areas. We measure the area of a triangle in square units like square meters (m²) or square centimeters (cm²).
