11.2 Surface Area 11.2 Surface Area of Prisms & of Prisms &
CylindersCylinders
PrismPrismA polyhedron with two
congruent faces (bases) that lie in parallel planes.
The lateral faces are parallelogramsThe height is the perpendicular distance between the bases
Surface Area (SA): the sum of the areas of its faces
Lateral Area (LA): the sum of the areas of the lateral faces
Surface AreaSurface area is found by
finding the area of all the sides and then adding those answers up.
How will the answer be labeled?
UnitsUnits22 because it is area!
Rectangular PrismHow many faces are on here? 6
Find the area of each of the faces.A
B
C
4
5 in
6Do any of the faces have the same area?
A = 5 x 4 = 20 x 2 =40
B = 6 x 5 = 30 x 2 = 60
C = 4 x 6 = 24 x 2 = 48
If so, which ones?
148 in2
Opposite faces are the same.
Find the SA
CubeAre all the faces the same? YES
4m
How many faces are there? 6
Find the Surface area of one of the faces.
A
4 x 4 = 16 Take that times the number of faces.X 6
96 m2 SA for a cube.
Triangular PrismHow many faces are there? 5
How many of each shape does it take to make this prism?
2 triangles and 3 rectangles = SA of a triangular prism
4
3
5
10 m
Find the surface area. Start by finding the area of the triangle.
4 x 3/2 = 6
How many triangles were there? 2
x 2= 12
Find the area of the 3 rectangles.
5 x 10 = 50 = front
4 x 10 = 40 = back
3 x 10 = 30 = bottom
SA = 132 m2What is the final SA?
Surface Area of a Right Surface Area of a Right PrismPrismThe surface area (SA) of a
right prism is:
SA = 2B + PhB = area of one baseP = perimeter of one baseh = height of the prism
2B represents the “base area”Ph represents the “lateral area”
Find lateral area & Find lateral area & surface areasurface area
Find lateral area and Find lateral area and surface areasurface area
Find lateral area & Find lateral area & surface areasurface area
Find lateral area & surface area
8 cm
3 cm
CylinderCylinder
A solid with congruent A solid with congruent circular bases that lie in circular bases that lie in parallel planes.parallel planes.
Lateral area: the area of Lateral area: the area of its curved surfaceits curved surface
Surface Area of a Right Surface Area of a Right CylinderCylinder
The surface area of a right cylinder is:
SA = 2B + Ph which can be written as:
SA = 2πr2 + 2πrh
Find lateral area & Find lateral area & surface areasurface area
Find total surface areaFind total surface area