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Worksheet

Extension & Challenge — Modelling with Measurement & Geometry

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Part A — Volume, Capacity & Cost

Designing real objects links volume (space inside, in m³), capacity (how much it holds, in litres) and cost. A useful conversion: 1 m³ = 1000 L.

A design task diagram of a rectangular garden bed showing its length, width and depth and the steps to work out volume, litres and bags of soil.
Design task: working out how much soil fills a garden bed.
1 A garden bed is 3 m long, 2 m wide and 0.3 m deep. Find its volume in cubic metres.

Volume =

2 Convert that volume to litres. (Remember 1 m³ = 1000 L.)

Answer: L

3 Soil is sold in 30 L bags. How many bags are needed to fill the bed?

Answer: bags

4 Each bag of soil costs $8. What is the total cost to fill the bed?

Answer:

5 A second bed is the same width and depth but twice as long. Without redoing all the working, explain how the volume and the number of bags change.
6 Design challenge. Design a rectangular garden bed with a volume as close as possible to 1 m³. Give its length, width and depth, and show the volume.

Part B — Measuring & Costing Real Spaces

Modelling a real job means choosing the right measure: perimeter for things that go around an edge (fencing, edging), and area for things that cover a surface (paving, paint). Watch your units and convert when needed.

1 A rectangular yard is 8 m by 5 m. Find the perimeter, then the cost of fencing it at $15 per metre.
2 The same yard is to be paved. Find its area, then the cost at $40 per square metre.
3 Complete these conversions.

(a) 2.5 m = cm

(b) 3500 mL = L

(c) 1.2 kg = g

4 Estimate, then calculate. A tin of paint covers 10 m². A wall is 4 m wide and 2.5 m high. Estimate, then work out how many tins are needed.
5 Reasoning. A square garden of side 6 m has a 1 m-wide path running all the way around the outside. What is the area of the path only?
6 Design and cost. Plan a rectangular vegetable plot no larger than 12 m². State its dimensions, the length of edging it needs, and the cost of edging at $6 per metre.