Area of a rectangle and units of area
Find the area of a rectangle with S = a · b, find an unknown side and learn the units of area: cm², dm², m², are, hectare. Section: Grade 4, area of a rectangle and units of area; equal figures are in the Grade 5 studio.
📖 Start here: read the steps of the “Lesson” in order (1, 2, 3 …) and answer each question. Then continue with “Practice”.
- Germany: grade 5
- Ukraine: grade 4
- Russia: grade 4
Guide
In Ukrainian Grade 4 the area of a figure is written S. The area of a rectangle is the product of two neighbouring sides: S = a · b, where a is the length and b the width. Area is measured in square units: mm², cm², dm², m², km².
If the area and one side are known, the other side is found by division: b = S : a. Units of area are related differently from units of length: 1 dm = 10 cm but 1 dm² = 10 · 10 = 100 cm².
Large plots of land are measured in ares and hectares: 1 а (ar) is the area of a square with side 10 m, that is 100 m²; 1 га (hectare) is the area of a square with side 100 m, that is 10 000 m² = 100 а.