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Measurement, STD2 M1 2021 HSC 12 MC

A block of land is represented by the shaded region on the number plane. All measurements are in kilometres. 
 

Which of the following is the approximation for the area of this block of land in square kilometres, using two applications of the trapezoidal rule?

  1. 99
  2. 19.8
  3. 39.6
  4. 72
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`B`

Show Worked Solution

`\text{Solution 1}`

`text(Area)` `≈ 6/2(1.2 +2) + 6/2(2+1.4)`
  `≈ 3(3.2) + 3(3.4)`
  `≈ 19.8\ text(km)^2`

  
`\text{Solution 2}`

`\text{Area}` `≈ \frac{6}{2} (1.2 + 2 \times 2 + 1.4)`
  `≈ 19.8 \ \text{km}^2`

 
`=> B`

Measurement, STD2 M1 2015 HSC 28c*

Three equally spaced cross-sectional areas of a vase are shown.
 

2UG 2015 29c

 
Use the Trapezoidal rule to find the approximate capacity of the vase in litres.   (3 marks)

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`3.3\ text(litres)`

Show Worked Solution

`text(Solution 1)`

`V` `≈ 15/2(45 + 180) + 15/2(180 + 35)`
  `≈ 15/2(225 + 215)`
  `≈ 3300\ text{mL   (1 cm³ = 1 mL)}`
  `~~3.3\ text(L)`

 

`text(Solution 2)`

`V≈ 15/2(45 + 2 xx 180 + 35)~~3.3\ text(L)`

Measurement, STD2 M1 EQ-Bank 5 MC

The shaded region represents a block of land bounded on one side by a road.
 

2UG-2005-12MC

What is the approximate area of the block of land, using the Trapezoidal rule?

  1.  720 m²
  2.  880 m²
  3.  1140 m²
  4.  1440 m²
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`A`

Show Worked Solution

`text(Area)` `≈ 20/2(23 + 15) + 20/2(15 + 19)`
  `≈ 10(38) + 10(34)`
  `≈ 720\ text(m²)`

 
`=> A`

Measurement, STD2 M1 EQ-Bank 22

The scale diagram shows the aerial view of a block of land bounded on one side by a road. The length of the block, `AB`, is known to be 90 metres.
 

Calculate the approximate area of the block of land, using three applications of the Trapezoidal rule.   (3 marks)

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`text{5175 m}^2`

Show Worked Solution

`text(Solution 1)`

`text(6 cm → 90 metres)`

` text(1 cm → 15 metres)`
 

`text(Height) = 2 xx 15 = 30\ text(metres)`

`text(Area)` `~~ 30/2(75 + 60) + 30/2(60 + 45) + 30/2(45 + 60)`
  `~~ 15(135 + 105 + 105)`
  `~~ 5175\ text(m)^2`

 

`text(Solution 2)`

`text(After converting from scale:)`

`text(Area)~~ 30/2(75 + 2 xx 60 + 2 xx 45 + 60)~~ 5175\ text(m)^2`

Measurement, STD2 M1 2013 HSC 15a*

The diagram shows the front of a tent supported by three vertical poles. The poles are 1.2 m apart. The height of each outer pole is 1.5 m, and the height of the middle pole is 1.8 m. The roof hangs between the poles.

2013 15a

The front of the tent has area `A\ text(m²)`. 

  1. Use the trapezoidal rule to estimate `A`.    (2 marks)

  2. Explain whether the trapezoidal rule give a greater or smaller estimate of `A`?   (1 mark)

Show Answers Only
  1. `3.96\ text(m²)`
  2. `text(The trapezoidal rule assumes a straight line between)`

     

    `text(all points and therefore would estimate a greater)`

     

    `text(area than the actual area of the tent front.)`

Show Worked Solution
a.    `A` `~~ h/2 [y_0 + 2y_1 + y_2]`
    `~~ 1.2/2 [1.5 + (2 xx 1.8) + 1.5]`
    `~~ 0.6 [6.6]`
    `~~ 3.96\ text(m²)`

 

b.  `text(The trapezoidal rule assumes a straight line between)`

`text(all points and therefore would estimate a greater)`

`text(area than the actual area of the tent front.)`