Area of triangles and quadrilaterals
Key Notes :
Area of a rectangle:
area=base . height
Learn with an example
What is the area of this square?

_______ square millimeters?
Find the side length of the square.
side: 2 mm
Use this number in the formula.
area= side . side
= 2.2
= 4
Now find the units. The lengths are measured in millimeters, so the area is measured in square millimeters.
The area is 4 square millimeters.
What is the area?

_________ square kilometers
Find the base and height of the parallelogram.
base: 6 km
height: 7 km
Use these numbers in the formula.
area = base . height
= 6.7
= 42
Now find the units. The lengths are measured in kilometers, so the area is measured in square kilometers.
The area is 42 square kilometers.
What is the area?

______ square kilometers
Find the base and height of the rectangle.
base: 8 km
height: 7 km
Use these numbers in the formula.
area= base . height
= 8 . 7
= 56
Now find the units. The lengths are measured in kilometers, so the area is measured in square kilometers.
The area is 56 square kilometers.
Let’s practice!