Area of parallelograms and triangles: 5th grade math lesson

What this lesson shows

Cut a triangle off a parallelogram and slide it over: a rectangle, so the area is base × height. A triangle is half of that.

The worked example

The lesson works this one step by step: a parallelogram, base 8 cm, height 4 cm, slanted side 5 cm. Then your kid tries one like it on paper.

The steps

Parallelogram: base × height
Triangle: half of base × height
Height is at a right angle
Not the slanted side

Helping at home

A parallelogram’s area is base times height, and a triangle’s is half of that. The height goes straight up from the base, at a right angle. The slanted side is not the height: leave it out.

If your kid gets stuck

Which number is the height?

Watch it with Lux

With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.

See how Lux works

Area of parallelograms and triangles