science

Rai, ngan, and tarang wa

Rai, ngan, and tarang wa is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rai, ngan, and tarang wa rather than just read about it. In short: The rai, ngan, and tarang wa or square wa are customary Thai units of area, used in the measurement of land. They are defined as exactly 1,600, 400, and 4 square metres, respectively (17,222, 4,306, and 43 sq ft).

Key takeaways

Rai, ngan, and tarang wa belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Rai, ngan, and tarang wa to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Rai, ngan, and tarang wa from memory before moving on to harder problems.

Reference excerpt

The rai, ngan, and tarang wa or square wa are customary Thai units of area, used in the measurement of land. They are defined as exactly 1,600, 400, and 4 square metres, respectively (17,222, 4,306, and 43 sq ft). The tarang wa (square wa, tarang meaning 'grid') is derived from the area of a square with sides of 1 wa (the Thai fathom). 1 ngan ('work') is equal to 100 square wa, and 1 rai ('field' or 'plantation') equals 4 ngan or 1 square sen. The units were standardised in square metres when Thailand (then Siam) adopted the metric system in 1923, although the Royal Survey Department was already reported in 1908 to be using the metre-based conversion for its cadastral maps. The units are commonly used for cadastre and property matters, and official and legal documents express areas of land in such units. They are sometimes notated in the abbreviated format rai-ngan-tarang wa, e.g. "4-2-25 rai", which means "4 rai, 2 ngan, and 25 tarang wa", though this is discouraged by some government documents.

Notes

References

Worked examples

Example 1 — a first encounter with Rai, ngan, and tarang wa

Start with the simplest possible case. Write down what Rai, ngan, and tarang wa claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rai, ngan, and tarang wa before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rai, ngan, and tarang wa ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rai, ngan, and tarang wa

In research: Rai, ngan, and tarang wa appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Rai, ngan, and tarang wa in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Rai, ngan, and tarang wa is common in secondary-school and first-year university syllabi. It links to neighbouring topics Thai units of measurement, Units of area, so understanding it makes those chapters shorter.
In everyday life: Look for Rai, ngan, and tarang wa outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rai, ngan, and tarang wa in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Rai, ngan, and tarang wa means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Rai, ngan, and tarang wa out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rai, ngan, and tarang wa in simple terms?

Why does Rai, ngan, and tarang wa matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rai, ngan, and tarang wa?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rai, ngan, and tarang wa.