1. **Problem Statement:**
We have several problems involving volumes and areas of prisms, cylinders, and tanks.
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### Problem 1: Swimming Pool Cross-Section and Volume
2. **Given:**
- Depth at AE = 2.1 m
- Depth at BC = 1 m
- AB = 6.5 m
- BC = 1 m
- ED = 3 m
- Width of pool = 4.6 m
3. **(i) Find length of DC:**
- Since AE and BC are vertical depths, and ED is vertical 3 m, DC is horizontal.
- Using the polygon properties and right angles, length DC = AB - BC = 6.5 - 1 = 5.5 m.
4. **(ii) Find area of uniform cross-section:**
- The cross-section is a polygon composed of rectangles and triangles.
- Area = sum of areas of rectangles and triangles.
- Calculate area of trapezium or polygon using coordinates or decomposition.
- Using average depth: average depth = (2.1 + 1)/2 = 1.55 m
- Area = length AB * average depth = 6.5 * 1.55 = 10.075 m²
5. **(b) Find volume of pool:**
- Volume = cross-sectional area * width
- Volume = 10.075 * 4.6 = 46.345 m³
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### Problem 2: Volume of Solid with Semicircular Top
6. **Given:**
- Base length = 22 mm
- Semicircle radius = 17 mm
7. **Volume formula:**
- Volume = base area * height
- Base area = rectangle area + semicircle area
- Rectangle area = length * width (width not given, assume uniform cross-section)
- Semicircle area = \( \frac{1}{2} \pi r^2 \)
8. **Calculate semicircle area:**
- \( \frac{1}{2} \pi (17)^2 = \frac{1}{2} \pi 289 = 144.5\pi \approx 454.0 \text{ mm}^2 \)
9. **Total cross-section area:**
- Assuming width = 22 mm (same as length), total area = rectangle + semicircle = 22 * 22 + 454 = 484 + 454 = 938 mm²
10. **Volume:**
- Volume = cross-section area * height (height not given, problem incomplete)
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### Problem 3: Cylindrical Can Fuel Volume
11. **Given:**
- Diameter = 6 cm
- Height = 12 cm
- Volume of liquid = 320 cm³
12. **(a)(i) Calculate volume of can:**
- Radius = 3 cm
- Volume = \( \pi r^2 h = \pi (3)^2 (12) = 108\pi \approx 339.29 \text{ cm}^3 \)
13. **(a)(ii) Volume of empty space:**
- Empty space = total volume - liquid volume = 339.29 - 320 = 19.29 cm³
14. **(a)(iii) Height of gap:**
- Volume of liquid = \( \pi r^2 h_{liquid} = 320 \)
- \( h_{liquid} = \frac{320}{\pi (3)^2} = \frac{320}{28.274} \approx 11.31 \text{ cm} \)
- Height of gap = total height - liquid height = 12 - 11.31 = 0.69 cm
15. **(b) Number of cans to fill tank:**
- Tank dimensions: 22 cm x 12 cm x 17 cm
- Tank volume = 22 * 12 * 17 = 4488 cm³
- Number of cans = \( \left\lfloor \frac{4488}{339.29} \right\rfloor = 13 \) cans
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### Problem 4: Rain Volume on Roof
16. **Given:**
- Roof area = 20 m * 8 m = 160 m²
- Rain depth = 1 cm = 0.01 m
17. **Volume of water:**
- Volume = area * depth = 160 * 0.01 = 1.6 m³
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**Final answers:**
- 1(i) Length DC = 5.5 m
- 1(ii) Area cross-section = 10.075 m²
- 1(b) Volume pool = 46.345 m³
- 3(a)(i) Volume can = 339.29 cm³
- 3(a)(ii) Empty space = 19.29 cm³
- 3(a)(iii) Height gap = 0.69 cm
- 3(b) Number of cans = 13
- 4 Volume rain = 1.6 m³
Volume Prisms
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