A parallelogram is a quadrilateral that has two pairs of parallel sides. The opposing sides must be of equal length and measure. A parallelogram has four vertices and four edges.
Understanding parallelograms:
Parallelograms are used for students to calculate and estimate angles. Children must also ensure that all angles in a parallelogram add up to the correct amount. The right amount is 360°. For example:
In parallelogram ‘a’, four angles need to be measured/estimated. Furthermore, each opposite angle must equal the same number, so the answer is:
A parallelogram is a 2D shape with two matching pairs of opposite sides that are parallel and equal in length. The angles inside two sides must add up to 180°, which means that the angles inside the entire shape must add up to 360°.
What are the five properties of a parallelogram?
There are five main properties of a parallelogram. So why not introduce your class to the properties of parallelograms and then test their knowledge with a quiz to ensure they understand everything?
- The opposite sides are parallel.
- Opposite sides agree – they are the same in length and angle.
- Opposite angles are in agreement – they are the same.
- Angles must add up to 360 degrees (180 degrees with consecutive angles that are supplementary).
- When one angle is correct, all other angles are right!
What are the four types of a parallelogram?
There are four types of parallelograms, including three particular types. The four types are parallelograms, squares, rectangles, and rhombuses.
It may sound silly to say that squares, rectangles, and rhombuses are types of parallelograms. So bear with me – consider the properties of each of those shapes. They are all 2D quadrilaterals, with pairs of opposite sides that are the same and opposite angles that match each other.
Calculating the area of parallelograms
A parallelogram is essentially just a rectangle that has been pushed over slightly. This means that you can use the same calculation to find the area of a parallelogram as you would calculate the area of a rectangle.
It is pretty simple, so be sure that children know how to show their work.
In the diagram above, you can see that the height of the parallelogram is 10cm, and the base is 12cm.
Using the base and height of the parallelogram, you’re able to calculate the area of a parallelogram:
base × height = area
Using the above question as an example, can you work out the area of the parallelogram? Here is the answer with the working is shown:
10cm× 12cm = 120cm²
This is the correct area of the parallelogram. Make sure to put the little squared symbol above the measurement to show that it is the area of the shape.
Calculating the height or base of a parallelogram
Using the area and base numbers of the parallelogram, you’re able to calculate the base. You must do the opposite sum to the one that calculates the area.
area÷ height = base
Using the above question as an example, let’s calculate the base of the parallelogram:
300cm² ÷ 20cm = 15cm
This is the correct height of the parallelogram.
Calculating the perimeter of a parallelogram
To calculate the perimeter of a parallelogram, you need to know the length of the sides (s) and the base (b).
The length of the sides is not the same as the height. You can see this by using your knowledge of triangles. The side of the parallelogram is longer than the height. If you created a right-angled scalene triangle utilizing the height of the parallelogram and the side as two of its edges, the side would be the longest edge of the parallelogram.
The formula for calculating the perimeter of a parallelogram is: 2(b+s)
