welcome : w e l c o m e MATHEMATICS ACTIVITY CLASS IN
TOPIC SURFACE AREAS AND VOLUMES : TOPIC SURFACE AREAS AND VOLUMES
PowerPoint Presentation : (ii) TO DETERMINE THE FORMULA FOR TOTAL SURFACE AREA OF A GIVEN CYLINDER. OBJECTIVES :- ACTIVTY NO. 12 ( i ) TO DETERMINE THE LATERAL SURFACE AREAOR C. S. A. OF A GIVEN CYLINDER WITH RADIUS ‘r’ AND HEIGHT ‘h’ .
Pre Requisite knowledge : Pre Requisite knowledge 1. Knowledge of right circular cylinder. 2. Area of rectangle (area = L x B square units). 3. Area and circumference of circle. ( A = π r 2 square units and C = 2 π r units)
Materials required : Materials required White chart paper A cylinder made of paper A pair of scissors Ruler Fevicol
Procedure : Procedure 1. Remove the circular ends of cylinder from top and bottom(Fig-1)
PowerPoint Presentation : h . 2 π r .
2. Now cut the cylinder vertically and open the lateral surface flat which is a rectangle (figure) : 2. Now cut the cylinder vertically and open the lateral surface flat which is a rectangle (figure) B C A D 2 π r h
PowerPoint Presentation : A D C B 2 π r h r . 3. Paste the cutout on chart paper and measure the length and breadth of the rectangle so formed .
PowerPoint Presentation :
observation : observation We observe that – 1. The base and top of the cylinder are circle, each of area π r 2 . 2. The length l of rectangle is the circumference of the base of the rectangle. C = 2 π r. 3. The breadth b of rectangle is the height of cylinder. b = h 4. Curved surface area of cylinder = area of the rectangle ABCD l × b = 2 π r × h = 2 π rh . 5. Total surface area of cylinder = C. S. A. + 2(area of base circle) T. S. A. = 2 π rh + 2 ( π r 2 ) = 2 π r(h + r)
result : result From above activity, we have learnt to derive formula for curved surface area (2 π rh ) and total surface area [2 π r(h + r)] of cylinder
Quiz on the chapter : Quiz on the chapter
HOME WORK : HOME WORK FIND THE C. S. A. AND T. S. A. OF A CYLINDERICAL TANK WITH RADIUS 21 cm AND HEIGHT 19 cm.
PowerPoint Presentation : THANKS A PRESENTATION BY H P PATEL , TGT MATHS JNV AMARKANTAK