Area and Land Measurements
Primary 4 · Mathematics
Area and Land Measurements
Lesson 4 of 5
20 min
Let's begin
Byiringiro's grandfather has a farm in Nyagatare. "Our farm is 2 hectares," he says proudly. "And our neighbour's banana plot is 35 ares."
Byiringiro knows square metres. But what are hectares and ares? Today you will learn the special units we use for land.
| Land unit | Same as | A square with sides of |
|---|---|---|
| 1 centiare (ca) | 1 m² | 1 m |
| 1 are (a) | 100 m² = 1 dam² | 10 m |
| 1 hectare (ha) | 100 a = 10 000 m² = 1 hm² | 100 m |
A full-size football pitch is about 105 m long and 68 m wide. That is 7 140 m², or about 71 ares. A hectare is 100 ares, so a hectare is bigger than a football pitch.
Farms, forests, tea estates and national parks are measured in hectares. A small garden or a plot for a house is often measured in ares or square metres.
Each land unit is 100 times the next one: ha → a → ca (m²).
Worked example 1
3 ha = ? a. 3 × 100 = 300 a.
Worked example 2
2 500 m² = ? a. 2 500 ÷ 100 = 25 a.
Worked example 3
4 ha 35 a = ? a. 4 ha = 400 a, and 400 + 35 = 435 a.
Worked example 4
1 200 a = ? ha. 1 200 ÷ 100 = 12 ha.
Worked example 5
2 ha = ? m². 2 × 10 000 = 20 000 m².
Careful! Do not mix up the are with the acre. The acre is a different, old unit. In Rwanda we use ares and hectares.
Tip
ha, a, ca: each is 100 times the next. Picture the squares: a centiare is 1 m on each side, an are is 10 m on each side, a hectare is 100 m on each side.
Work each one in your exercise book first. Then tap Show answer to check.
5 ha = ___ a
Answer: 500 a, because 5 × 100 = 500.
800 m² = ___ a
Answer: 8 a, because 800 ÷ 100 = 8.
7 a = ___ m²
Answer: 700 m².
2 ha 40 a = ___ a
Answer: 240 a. 2 ha = 200 a, and 200 + 40 = 240.
Is a 1 ha field bigger or smaller than 9 000 m²?
Answer: Bigger. 1 ha = 10 000 m², which is more than 9 000 m².
What you learned today
Sources and credits
Written by Ganzaa. The stories, drawings and practice questions are original.
Quick check
