geometry section 12-2
TRANSCRIPT
ESSENTIAL QUESTIONS
• How do you find lateral areas and surface areas of prisms?
• How do you find lateral areas and surface areas of cylinders?
VOCABULARY1. Lateral Face:
2. Lateral Edge:
3. Base Edge:
4. Altitude:
The surfaces of a polyhedron that are not bases
VOCABULARY1. Lateral Face:
2. Lateral Edge:
3. Base Edge:
4. Altitude:
The surfaces of a polyhedron that are not bases Formed where the lateral faces intersect
VOCABULARY1. Lateral Face:
2. Lateral Edge:
3. Base Edge:
4. Altitude:
The surfaces of a polyhedron that are not bases Formed where the lateral faces intersect
Formed where the lateral faces intersect the base(s)
VOCABULARY1. Lateral Face:
2. Lateral Edge:
3. Base Edge:
4. Altitude:
The surfaces of a polyhedron that are not bases Formed where the lateral faces intersect
Formed where the lateral faces intersect the base(s)
The perpendicular segment that joins the bases of a prism/cylinder
VOCABULARY5. Height:
6: Lateral Area:
7. Axis:
Another word for the altitude of a prism/cylinder The sum of the areas of the lateral faces
VOCABULARY5. Height:
6: Lateral Area:
7. Axis:
Another word for the altitude of a prism/cylinder The sum of the areas of the lateral faces
In a cylinder, this is the segment whose endpoints are the centers of the circular bases
EXAMPLE 1Find the lateral area of the regular hexagonal prism.
L = Ph
P = 5(6) = 30 cm
L = 30(12) = 360 cm2
SURFACE AREA OF A PRISM
L = Lateral Area
P = Perimeter of the Base
SA = L + 2B or SA= Ph + 2B
B = Area of the Base
SURFACE AREA OF A PRISM
L = Lateral Area
P = Perimeter of the Base
h = height of the prism
SA = L + 2B or SA= Ph + 2B
B = Area of the Base
EXAMPLE 2Find the surface area of the rectangular prism.
SA = 4(6)(10) + 2(6)(6)
SA = 312 in2
SA = L + 2B
LATERAL AREA OF A CYLINDER
L = Lateral Area
r = Radius of the Base
h = Height of the Cylinder
L = 2πrh
SURFACE AREA OF A CYLINDER
L = Lateral Area
r = Radius of the Base
SA = L + 2B or SA = 2πrh + 2πr2
B = Area of the Base
SURFACE AREA OF A CYLINDER
L = Lateral Area
r = Radius of the Base
h = Height of the Cylinder
SA = L + 2B or SA = 2πrh + 2πr2
B = Area of the Base
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
L = 2πrh
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
L = 2πrhL = 2π (14)(18)
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
L = 2πrhL = 2π (14)(18)
L ≈ 1583.36 ft2
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2B
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2BSA = 2πrh + 2πr2
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2B
SA = 2π (14)(18) + 2π (14)2SA = 2πrh + 2πr2
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2B
SA = 2π (14)(18) + 2π (14)2SA = 504π + 392π
SA = 2πrh + 2πr2
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2B
SA = 2π (14)(18) + 2π (14)2SA = 504π + 392π
SA = 896π
SA = 2πrh + 2πr2
EXAMPLE 3Find the lateral area and the surface area of the cylinder. Round to the nearest hundredth.
SA = L + 2B
SA = 2π (14)(18) + 2π (14)2SA = 504π + 392π
SA = 896π ≈ 2814.87 ft2
SA = 2πrh + 2πr2