Area of Parallelograms and Rhombi Examples

Solve for the area of a parallelogram with a base that's 7 inches long and a height that's 6 inches long.

As long as we know the base and the height of a parallelogram, we should be able to calculate its area. Really, it's not rocket science.

A = bh
A = 7 in × 6 in
A = 42 in²

A parallelogram has an area of 88 mm² and a height of 11 mm. What is its base length?

This requires the same A = bh formula that we've been using all along. This time, we have to solve for b, and luckily, we know A and h.

A = bh
88 mm² = b × 11 mm
8 mm = b

Calculate the area of a rhombus with diagonals of length 8 km and 9 km.

We know that rhombi have their own special formula when diagonals are involved. Knowing both diagonals is all it takes.

A = ½d₁d₂
A = ½ × 8 km × 9 km
A = 36 km²

Calculate the area of a rhombus with diagonals of 9 inches and 1 foot.

We can use the same diagonal formula as before, but we need to be careful about units. Our final units should be in either in² or ft². To do that, we have to convert the units of one of the diagonals. We like working with whole numbers, so let's make 1 foot = 12 inches.

Now, we can plug d₁ = 9 in and d₂ = 12 in into the formula.

A = ½d₁d₂
A = ½ × 9 in × 12 in
A = 54 in²

If we had gone with feet, the area would have been 0.375 ft².