Trapezoid area online calculator

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Welcome to the Trapezoid Area Calculator, where you can easily find the area of a trapezoid.

Anatomy of a Trapezoid

Before we dive into the intricacies of finding the area of a trapezoid, let's first understand its basic structure. A trapezoid is a four-sided geometric shape characterized by having two parallel sides, typically denoted as 'a' and 'b,' and two non-parallel sides, known as 'c' and 'd.' These parallel sides are often referred to as the bases of the trapezoid.

One remarkable property of trapezoids is that the sum of all their internal angles always equals 360°. Furthermore, if we examine the angles located on the same side of one of the legs (c or d), their sum is always 180°.

Internal Angles of a Trapezoid

Let's take a moment to discuss the internal angles of a trapezoid in more detail:

  • The angles at the vertices where the bases 'a' and 'c' meet are called adjacent angles.
  • The angles at the vertices where the bases 'b' and 'd' meet are also adjacent angles.
  • The angles located between the bases 'a' and 'd' are known as opposite angles.

Calculating the Area of a Trapezoid

Now that we've grasped the fundamental elements of a trapezoid, let's move on to calculating its area. To find the area of a trapezoid, you can use the following formula:

A = ½ (a + b) h


  • A represents the area of the trapezoid.
  • a and b are the lengths of the two parallel sides (bases).
  • h is the height, which is the perpendicular distance between sides a and b.

Let's illustrate this with an example:


Suppose you have a trapezoid with base 'a' measuring 6 units, base 'b' measuring 10 units, and a height 'h' of 4 units. To find its area, plug these values into the formula:

A = ½ (6 + 10) × 4

A = ½ (16) × 4

A = 8 × 4

A = 32 square units

So, the area of this trapezoid is 32 square units.

IV. Calculating the Perimeter of a Trapezoid

While we're on the topic of trapezoids, it's also useful to know how to quickly calculate their perimeter. The perimeter of any polygon is simply the sum of the lengths of its sides. For a trapezoid, you can use the following formula:

P = a + b + c + d


  • P represents the perimeter of the trapezoid.
  • a and b are the lengths of the parallel sides (bases).
  • c and d are the lengths of the non-parallel sides.

This formula simply adds up the lengths of all four sides of the trapezoid, giving you its perimeter.

Let's Sum It Up

In conclusion, trapezoids are remarkable geometric shapes with two parallel sides and two non-parallel sides. Their internal angles have specific properties, and you can easily find the area and perimeter of a trapezoid using the provided formulas. The area formula, A = ½ (a + b) h, and the perimeter formula, P = a + b + c + d, are valuable tools for geometry enthusiasts and anyone dealing with shapes in real-world applications.

Whether you're a student learning about geometry or someone working in a field where geometric shapes play a crucial role, understanding trapezoids and their properties is an essential skill. Now that you've learned the basics, you can confidently tackle problems involving these intriguing four-sided figures.

Feel free to explore further and practice your newfound knowledge with trapezoid area calculator tools available online. Happy learning!

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