smc-6519-20-Length/Area

Measurement, STD1 M1 2023 HSC 1 MC

What is \(4.2681\) when rounded to \(3\) decimal places?

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\(C\)

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\(4.2681 \approx\ 4.268 \ (3\ \text{d.p.})\)

\(\Rightarrow C\)

A measurement of 72 cm is increased by 20% and then the result is decreased by 20%.

What is the new measurement, correct to the nearest centimetre?

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`B`

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STRATEGY: Students confident in this area could save time in the calculations as follows: `72 xx 1.2 xx 0.8“ = 69.12`

`text(72 increased by 20%)`

`= 72 + (text(20%) xx 72) = 86.4\ text(cm)`

`text(86.4 decreased by 20%)`

`= 86.4\ – (text(20%) xx 86.4) = 69.12\ text(cm)`

`=> B`

How many square centimetres are in 0.0075 square metres?

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`C`

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`text{Since 1 m}^2`	`= 100\ text(cm) xx 100\ text(cm)`
	`= 10\ 000\ text{cm}^2`

♦♦♦ Mean mark 19%.

`:.0.0075\ text{m}^2`	`= 0.0075 xx 10\ 000`
	`= 75\ text{cm}^2`

`=> C`