Step by step
The question
Question: find the area of a parallelogram with base 8 cm and height 5 cm.
1 Make a rectangle
A parallelogram has two pairs of parallel sides.
It looks like a rectangle pushed over.
The height goes straight up from the base.
It makes a right angle with the base.
Cut off the triangle at the left end.
Move it to the right end.
It fits exactly.
Now it is a rectangle, 8 cm long and 5 cm high.
Nothing was added or lost, so the area is the same.
2 Base times height
So the area is base times height: A = b × h.
Now put the numbers in: b = 8 and h = 5.
8 times 5 is 40.
So the area is 40 cm².
3 Check
Let's check another way.
A line from corner to corner cuts it into two triangles.
Each triangle is half of base times height.
Both have base 8 and height 5.
We get 40 again.
So the area is right!
Let's look back.
First: make a rectangle.
Then: base times height.
Last: check.