AREA AND VOLUME

1. AREA AND VOLUME Form 1 Mathematics Chapter 7

2. Reminder • Lesson requirement • Textbook 1B • Workbook 1B • Notebook • Folder • Before lessons start • Desks in good order! • No rubbish around! • No toilets!

3. Result of CBQ (Ch. 9) • Result of Close Book Quiz • Full mark: 40 and 10 bonus • Highest: 44 • Lowest: 10 • Average: 23.8 • Number of students between 10 – 19: 13 • Number of students between 0 – 9: 0 • Major Problems • Cannot get the drawing in rotation • Cannot get the coordinates in transformation • Mix up the rotation and reflection

4. Result of CBQ (Ch. 9) • Result of Close Book Quiz • 9th place: KO Ka Chung Boston LIN Long Chak, Vincent • 8th place: FU Ling Yin, Larry • 7th place: LAU Cheuk Hei, Anson • 6th place: CHEN Yi, David • 5th place: CHAN Tsz Long, Sam • 4th place: YUEN Tin Wai, Timmy • 2nd place: LI Ming Chun, Edward WU SHAN Hao Yi • 1st place LI Sai Kong Congratulations!!!!!! Well done!!!!!!

5. =  base  height 1 2 Area of plane figures (p.2) 1. Area of triangle 2. Area of square = length  length 3. Area of rectangle = length  width

6. 1 2 =  sum of lengths of parallel sides  height Area of plane figures (p.2) 4. Area of parallelogram = base  height 5. Area of trapezium

7. 1 2 1 2 = 3  3 + (3 + 6)  2 cm2 = 10  4 –  2  2 cm2 Calculating areas (p.3) • Splitting Method • Filling Method Area of the figure = 18 cm2 Area of the figure = 38 cm2

8. Time for Practice • Pages 10 – 11 of Textbook 1B • Questions 5 – 18 • Pages 1 – 3 of Workbook 1B • Questions 1 – 5

9. WORKBOOK

10. WORKBOOK 16 36 10 260 cm2 36 36 10 (18  26) cm2 = 468 cm2 260 468 728 cm2

11. WORKBOOK 3 3 18 cm2 728 18 710 cm2

12. Volume of Simple Solids (p.3) 1. Volume of cube = length  length  length 2. Volume of cuboid = length  width  height

13. base base lateral faces PRISMS (柱體, P.12) • A solid with uniform cross-section in the shape of a polygon is called a prism. • A prism is named and classified according to the shape of its base. • The perpendicular distance between the two parallel bases of a prism is called its height (or length). • The faces (other than the two bases) of a prism are called lateral faces. height Triangular prism

14. Volume of Prisms (p.17) • Volume = area of base  height • e.g. Volume of the solid = 260  20 cm3 = 5200 cm3

15. Surface Areas of Prisms (p.14) • Total surface area = areas of the two bases + total area of all lateral faces • e.g. Total surface area of the solid = [2  260 + 6  (20  10)] cm2 = 1720 cm2

16. Volume of Prisms • Volume of the triangular prism = ? • Area of the base of the prism = ( 7  4  2 ) cm2 = 14 cm2 • So, the volume = ( 14  10 ) cm3 = 140 cm3

17. Volume of Prisms • Volume of the rectangular prism (cuboid) = ? • The volume = [ ( 5  3 )  6 ] cm3 = 90 cm3 • The volume = [ ( 3  6 )  5 ] cm3 = 90 cm3 • The volume = [ ( 5  6 )  3 ] cm3 = 90 cm3

18. Volume of Prisms • Find the volume of the prism. Area of base Volume of prism = (12  7 – 8  5) cm2 = 44 cm2 = 44  11 cm3 = 484 cm3

19. 1 2 = (6 + 12)  4 cm2 Volume & Surface Area of Prisms • The figure shows a gold ingot in the shape of a prism. Its base is a trapezium, and the other faces are rectangles. If the volume of the gold ingot is 540 cm3, find(a) the value of d, (b) the total surface area of the gold ingot. (a) Area of trapezium ∴ The volume of the gold ingot i.e. 36d = 540 d = 15 (b) Total surface area of the gold ingot = [2  36 + 2  (15  5) + 15  12 + 15  6] cm2 = 492 cm2 = 36 cm2 = 36d cm3

20. Time for Practice • Pages 22 – 23 of Textbook 1B • Questions 10 – 20 • Pages 6 – 7 of Workbook 1B • Questions 3 – 6

21. WORKBOOK

22. WORKBOOK 8 8 8 512 5 10 4 cm3 200 200 12d 512 4 3 d 12d = 312 12d cm3 26

23. WORKBOOK 2.5 1 6 15 cm2 19 15 4 cm2 4 2 cm2 2 2.5 5 cm3 3 1 2 6 cm3 5 cm3 6 cm3 B

24. Reminder • Missing Homework, Re-do Homework • Today! • SHW (I) • Today! • SHW (II) • 22 Mar (Fri) • Open Book Quiz • 22 Mar (Fri) • Close Book Quiz • 26 Mar (Tue)

25. Enjoy the world of Mathematics! Ronald HUI