To find the area of a parallelogram, the most common formula is: Area = base × height
- The base (b) is the length of one side of the parallelogram.
- The height (h) is the perpendicular distance from the base to the opposite side (not the side length if the parallelogram is slanted).
This formula works because a parallelogram can be rearranged into a rectangle with the same base and height, so their areas are equal
How to apply the formula:
- Identify the base of the parallelogram.
- Measure the height, which must be perpendicular to the base.
- Multiply the base length by the height.
Example:
If the base is 10 cm and the height is 8 cm, then the area is:
Area=10×8=80 cm2\text{Area}=10\times 8=80\text{ cm}^2Area=10×8=80 cm2
Alternative formulas if height is unknown:
- If you know the lengths of two adjacent sides aaa and bbb and the angle θ\theta θ between them, use:
Area=a×b×sin(θ)\text{Area}=a\times b\times \sin(\theta)Area=a×b×sin(θ)
- If you know the lengths of the diagonals d1d_1d1 and d2d_2d2 and the angle ϕ\phi ϕ between them, use:
Area=12×d1×d2×sin(ϕ)\text{Area}=\frac{1}{2}\times d_1\times d_2\times \sin(\phi)Area=21×d1×d2×sin(ϕ)
These formulas come from trigonometry and are useful when the height is not directly known
. Summary:
Known values| Formula
---|---
Base and height| Area=b×h\text{Area}=b\times hArea=b×h
Two sides and included angle| Area=a×b×sin(θ)\text{Area}=a\times b\times
\sin(\theta)Area=a×b×sin(θ)
Diagonals and angle between|
Area=12×d1×d2×sin(ϕ)\text{Area}=\frac{1}{2}\times d_1\times d_2\times
\sin(\phi)Area=21×d1×d2×sin(ϕ)
This allows you to calculate the area of any parallelogram using whichever measurements are available.