What you’ll learn
Find area of parallelograms.
Key idea
Parallelogram area uses the full base-height product, independent of the slant.
Use the perpendicular height and full base-height product; a slanted side and a triangle half factor are not valid substitutes.
Worked example
Enter the exact value or ordered values in the format requested below.
A parallelogram has base 3 cm, perpendicular height 6 cm and slanted side 7 cm. Enter its numerical area in square centimeters.
- The perpendicular height is 6 cm, whereas the slanted side is 7 cm.
- A=bh=3×6=18 square centimeters; no half factor applies.
Answer: 18
Quick Check
Evaluate a worked attempt at find area of parallelograms, identify the first invalid step, and provide the correction.
For a parallelogram with base 5 cm, perpendicular height 9 cm and slanted side 10 cm, a student writes Step 1: A=bh. Step 2: use h=10, obtaining A=50 cm². Locate the first invalid step and correct the area.