GEOMETRYSuccess depends upon previous preparation and without such preparation there is sure to be failure.

Confucius

Today: 12.2 Instruction Practice

12.2 Surface Areas of Prisms and Cylinders

Objectives: Know the terms for prisms Find the surface area for prisms Know the terms for cylinders Find the surface area for cylinders

Vocabulary: prism, bases, lateral faces, lateral area, surface area, cylinder, height

Prism: a polyhedron with two congruent bases that are

parallel.

The other faces (called lateral faces) are parallelograms made by connecting the bases.

Third dimension is height of WHOLE FIGURE.

Lateral Area: Area of Lateral Faces

Surface Area: Sum of ALL Faces

General Formula for Surface Area: SA = 2B + Ph where B = Area of Base, P = Perimeter of Base and h = height of whole figure

Find the surface area of the figure: 10 in

6 in

4 in

General Formula for Surface Area: SA = 2B + Ph where B = Area of Base, P = Perimeter of Base and h = height of whole figure

Find the surface area of the figure:

SA = 1979 cm2

You are working for Macy’s wrapping presents over the holiday season. You receive an order to wrap 15 boxes that are 12 in by 5 in by 2.5 in each. The roll of wrapping paper you have covers 20 square feet, do you have enough to wrap all the presents?

Find the surface area of the figure:

Not a prism… but close

Cylinder: a solid with two circular bases that are parallel.

4 in.

7 in.

General Formula for Surface Area: SA = 2B + Ph where B = Area of Base, P = Perimeter of Base and h = height of whole figure

What needs to change?

General Formula for Surface Area: SA = 2B + Ch where B = Area of Base, C = Circumference and h = height of whole figure

Find the surface area of a right cylinder that has a diameter of 10” and a height of 10”.

EXACT SA = 150in2

Approx SA = 471 in2

If the surface area of a right cylinder is 648 feet squared and the height is 15 feet, find the radius of the base.

Assignment: 12.2 p 850 #13, 15,

17, 19, 27, 33, 37, 45 Quiz 12.1 – 12.3

Friday

GEOMETRYSuccess depends upon previous preparation and without such preparation there is sure to be failure.

Confucius