Area of a Parallelogram
In this lesson, we will learn about the area of a parallelogram.
About This Lesson
In this lesson, we will:
Learn about the formula for the area of a parallelogram
See an example on using the formula to calculate a parallelogram's area
See another example on using the formula to calculate the height of a parallelogram
below will explain more.
A parallelogram has two pairs of parallel sides and its opposite sides are equal in length. These properties are shown on the right.
Now, if the parallelogram has the base
and the height
, the area,
, of the parallelogram will be:
The math video below will give more explanations on this. Also, we will see some examples on how to use this formula.
Your browser does not support Flash or HTML5 video. You can:
upgrade your browser
try this direct link
If the above player doesn't work,
try this direct link
Math Video Transcript
00:00:03.170 In this lesson, we will learn about the area of a parallelogram. 00:00:08.120 Consider this parallelogram with the base B and the height H. 00:00:14.190 Now, to find the area of this parallelogram, A, let's observe this parallelogram carefully. 00:00:22.060 If we cut out this portion and place it here. Observe that, we now have a rectangle. 00:00:30.150 Therefore, we can say that the area of this parallelogram is that same as, the area of this rectangle. 00:00:38.050 In the previous lesson, we learned that the area of a rectangle can be found by multiplying its length and width together. 00:00:46.240 Similarly, we can find this area, by multiplying the base, and height together. Hence, we have B multiply H which is the same as BH. 00:00:59.180 Let's change this back to a parallelogram. Now, the area of this parallelogram, A, equals to BH. 00:01:09.210 Note that, it is very important to include the unit. Since this is the formula for area, its unit will be in the form of square unit. 00:01:19.160 We will see more explanations on this, in the upcoming example. 00:01:25.020 Now, let's see some examples on using this formula. 00:01:29.220 Find the area of this parallelogram when its base is 5cm, and its height is 3cm. 00:01:37.110 To solve this, we start with the formula for the area of a parallelogram, A equals to BH. 00:01:44.240 Since the base is given as 5cm, we can substitute b with 5. 00:01:51.010 Similarly, since the height is given as 3cm, we can substitute h with 3. 00:01:57.240 Next, we can simplify by multiplying 5 with 3. This gives 15. 00:02:05.020 Note that, this number has no meaning unless we include the unit for it. 00:02:10.070 Since the units are given in centimeter, the unit for the area will be in square centimeter. 00:02:16.070 Hence, the area of this parallelogram is 15 square centimeter. 00:02:22.240 Next example, given that the area of this parallelogram is 20 square feet, and its base is 4ft. Find its height. 00:02:32.130 Again, we start with the formula for the area of a parallelogram, A equals to BH. 00:02:39.190 Now, since the area, and the base are given, we can find the height by solving this equation for H. Here’s how. 00:02:48.210 Since the area is given as 20 square feet, we can substitute A with 20. 00:02:54.210 Similarly, since the base is given as 4cm, we can substitute b with 4. 00:03:01.220 Now we have, 4H equals to 20. 00:03:06.080 Let's rewrite this equation so that it will look neater. 00:03:10.120 To find h, we need to remove 4. We can do so by dividing both sides of the equation with 4. 00:03:19.070 By doing so, we have, H equals to 20 over 4. 00:03:25.090 20 divides by 4, gives 5. 00:03:29.040 Now, this number is meaningless unless we include the unit for it. 00:03:34.030 Since the base is in feet, the height of the parallelogram will be in feet. 00:03:40.000 Therefore, the height of this parallelogram is 5 ft. 00:03:45.220 That is all for this lesson. Try out the practice question to further your understanding.
Practice Questions & More
Multiple Choice Questions (MCQ)
Now, let's try some MCQ questions to understand this lesson better.
You can start by going through the series of
questions on the area of a parallelogram
or pick your choice of question below.
on finding the area of a parallelogram
on finding the height of a parallelogram
Return to Home Page
. All Rights Reserved.
This is an offline version of MathExpression.com for the WorldPossible.org's RACHEL project. Enjoy!