Surface area and volume
description
Transcript of Surface area and volume
• opposite sides are equal
• each angle is of 900
• Diagonals are equal &bisect each other
SQUARE
• All sides are equal
• each angle is of 900
• Diagonals are equal & bisect each other at 900
CICRLE
RequirementEdge/side
Cube
Cube
• Volume = Base area x height
= L x L x L
= L3
L
L
L
• Total surface area = 2LxL + 2LxL + 2LxL
= 6L2
•Diagonal of cube=√3×L unit
•Lateral surface area=perimeter of base ×height =4×L3 unit3
Side 2
Bottom
Back
Top
Side 1Front
Side 2
Bottom
Back
Top
Side 1Front
Length (L)Breadth (B)
Height (H)
Cuboid
H
B
LH
B
H
L
L
L
H
B
L
H
B
H
L
L
Total surface Area = L x H + B x H + L x H + B x H + L x B + L x B
= 2 LxB + 2BxH + 2LxH
= 2 ( LB + BH + LH )
Total surface Area
Lateral surface area=2(L+B)H unit2
Volume=area of base×height =L×B×H unit3
Diagonal of cuboid=√L2+B2+H2
Example:
7 cm
4 cm
8 cm
Here:
l=8cm
B=4cm
H=7cm
SA=2(lb+bh+lh)=2(8X4+4x7+8x7)
=2(64+56+112)
=232cm²
V = lwh
V = 8(4)(7)
V = 224 cm³
Curved surface area of cylinder
Curved surface area of an object is the area of outer covering of it. If a rectangular paper is folded ,the length becomes the circumference and the breadth becomes the height. So csa of a cylinder is 2πr x height.
Curved surface area of cylinder=2πrh
Circumference of circle = 2 π r
Area covered by cylinder = Surface area of of cylinder = (2 π r) x( h)
r h
Outer Curved Surface area of cylinder
It is the area covered by the outer surface of a cylinder.
Formation of Cylinder by bangles
Circumference of circle = 2 π r
r
Total Surface area of a solid cylinder
=(2 π r) x( h) + 2 π r2
Curved surface
Area of curved surface +area of two circular surfaces=
circular surfaces
= 2 π r( h+ r)
2πr
h
r
h
Surface area of cylinder = Area of rectangle= 2 πrh
Other method of Finding Surface area of cylinder with the help of paper
Here:
r=3.1
H=12
SA = 2πrh + 2πr²
SA = 2π(3.1)(12) + 2π(3.1)²
SA = 2π (37.2) + 2π(9.61)
SA = π(74.4) + π(19.2)
SA = 233.7 + 60.4
SA = 294.1 in²
Right Circular Cone
RequirementRadius(r)Height(h)Slant height(l)At least 2 must be given
(l)2= (h)2 + (r)2
l =√ h2 + r2
l2πr
l
Area of a circle having sector (circumference) 2π l = π l 2
Area of circle having circumference 1 = π l 2/ 2 π l
So area of sector having sector 2 π r = (π l 2/ 2 π l )x 2 π r = π rl
Surface area of cone
3( V ) = π r2h
r
h h
r
Here the vertical height and radius of cylinder & cone are same.
3( volume of cone) = volume of cylinder
V = 1/3 π r2h
if both cylinder and cone have same height and radius then volume of a cylinder is three times the volume of a cone ,
Volume = 3V Volume =V
Mr. Mohan has only a little jar of juice he wants to distribute it to his three friends. This time he choose the cone shaped glass so that quantity of juice seem to appreciable.
SphereRequirementRadius(r)
Height = diameter
V1
r
V=1/3 πr2h
If h = r thenV=1/3 πr3
rr
If we make a cone having radius and height equal to the radius of sphere. Then a water filled cone can fill the sphere in 4 times.
V1 = 4V = 4(1/3 πr3)
= 4/3 πr3
4( 1/3πr2h ) = 4( 1/3πr3 ) = V
h=r r
Volume of a Sphere
Click to See the experiment
Here the vertical height and radius of cone are same as radius of sphere.
4( volume of cone) = volume of Sphere
V = 4/3 π r3
r
Hemisphere
RequirementRadius/ diameter
Height=radius
Frustum of Cone
VolumeV = π/12 h (D2 + D d + d2) (9a)
m = ( ( (D - d) / 2 )2 + h2)1/2 (9c)
Cone shape
Cylindrical shape
Bottle
VolumeV = π/4 h (D2 - d2) (5)
Hollow Cylinder
TRIANGULAR PRISM
To find the surface area of a triangular prism you need to be able to imagine that you can take the prism apart like so:Notice there are TWO congruent triangles and THREE rectangles. The rectangles may or may not all be the same.
Find each area, then add.
Example:
8mm
9mm
6 mm 6mm
Find the AREA of each SURFACE
1. Top or bottom triangle:
A = ½ bh
A = ½ (6)(6)
A = 18
2. The two dark sides are the same.
A = lw
A = 6(9)
A = 54 ADD THEM ALL UP!
18 + 18 + 54 + 54 + 72
SA = 216 mm²
3. The back rectangle is different
A = lw
A = 8(9)
A = 72
PYRAMID
Volume
V = 1/3 h A1 (6)
whereA1 = area of base (m2, ft2)
h = perpendicular height of pyramid (m, ft)
SurfaceA = ∑ sum of areas of triangles forming sides
+ Ab (6b)
wherethe surface areas of the triangular faces will have different formulas for different shaped bases
FRUSTUM OF PYRAMID
VOLUMEV = h/3 ( A1 + A2 + (A1 A2)1/2) (7)
Zone of SPHERE
V = π/6 h (3a2 + 3b2 + h) (11a)
Am = 2 π r h (11b)
A0 = π (2 r h + a2 + b2) (11c)
V = π/6 h (3/4 s2 + h2) = π h2 (r - h/3) (12a)
Am = 2 π r h = π/4 (s2 + 4 h2) (12b)
V = 2/3 π r2 h (13a)A0 = π/2 r (4 h +
s) (13b)
V = π/6 h3 (14a)
A0 = 4 π ((R + r)3 (R -
r))1/2 = 2 π h (R + r) (14b)h = 2 (R2 - r2)1/2 (14c)
V = 2/3 π R2 h (15a)
A0 = 2 π R (h + (R2 -
h2/4)1/2) (15b)h = 2 (R2 - r2)1/2 (15c)
V = π2/4 D d2 (16a)
A0 = π2 D d (16b)
V = 2/3 r2 h (18a)
Am = 2 r h (18b)
A0 = Am + π/2 r2 + π/2 r
(r2 + h2)1/2 (18c)
V = π/4 d2 h (17a)Am = π d h (17b)
A0 = π r (h1 + h2 + r
+ (r2 + (h1 - h2)2/4)1/2) (17c)
V ≈ π/12 h (2 D2 + d2) (19a)
VolumeV = A1 h (3a)whereA1 = side area (m2, ft2)