The problem asks us to find the volume of a cylindrical litter bin in m³ to 2 decimal places (part a), and then to find the volume of rubbish that can be put in the bin below the level of the hole, also in m³ to 2 decimal places (part b). The dimensions of the cylinder are given in centimeters: diameter = 60 cm and height = 90 cm for the entire bin. The hole is located 70 cm from the base.

GeometryVolumeCylinderUnits ConversionProblem Solving
2025/6/10

1. Problem Description

The problem asks us to find the volume of a cylindrical litter bin in m³ to 2 decimal places (part a), and then to find the volume of rubbish that can be put in the bin below the level of the hole, also in m³ to 2 decimal places (part b). The dimensions of the cylinder are given in centimeters: diameter = 60 cm and height = 90 cm for the entire bin. The hole is located 70 cm from the base.

2. Solution Steps

(a) Find the volume of the litter bin.
The formula for the volume of a cylinder is:
V=πr2hV = \pi r^2 h
where rr is the radius and hh is the height.
The diameter is 60 cm, so the radius is r=60/2=30r = 60/2 = 30 cm.
The height of the cylinder is h=90h = 90 cm.
Therefore, the volume in cm³ is:
V=π(302)(90)=π(900)(90)=81000πV = \pi (30^2) (90) = \pi (900)(90) = 81000\pi cm³.
To convert to m³, we divide by (100)3=1000000(100)^3 = 1000000:
V=81000π1000000=0.081πV = \frac{81000\pi}{1000000} = 0.081\pi m³.
V0.0813.141592653590.257610597240.26V \approx 0.081 * 3.14159265359 \approx 0.25761059724 \approx 0.26 m³ (to 2 decimal places).
(b) Find the volume of rubbish below the hole.
The height from the base to the hole is 70 cm.
Using the same radius r=30r = 30 cm, we calculate the volume up to the hole.
V=πr2h=π(302)(70)=π(900)(70)=63000πV = \pi r^2 h = \pi (30^2) (70) = \pi (900) (70) = 63000\pi cm³.
To convert to m³, we divide by (100)3=1000000(100)^3 = 1000000:
V=63000π1000000=0.063πV = \frac{63000\pi}{1000000} = 0.063\pi m³.
V0.0633.141592653590.19792033710.20V \approx 0.063 * 3.14159265359 \approx 0.1979203371 \approx 0.20 m³ (to 2 decimal places).

3. Final Answer

(a) The volume of the litter bin is 0.26 m³.
(b) The volume of rubbish that can be put in the bin below the hole is 0.20 m³.

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