11.2 SURFACE AREA OF PRISMS AND CYLINDERS

Prism – A polyhedron that has two identical ends (bases) and all flat sides ( lateral faces)

Green – BASES

Other– LATERAL FACES

Altitudes Any segment joining the two planes that

contain both bases and is perpendicular to both.

The dashed lines are altitudes.

Adjacent lateral faces intersect at the black solid lines called LATERAL EDGES.

In some prisms lateral edges are also altitudes, BUT NOT ALWAYS.

LATERAL EDGES are all parallel.

The height of the prism is the length of the altitude, not necessarily a vertical distance.

Right Prisms A right prism is any prism in which the

lateral faces are all rectangles.

In right prisms the lateral edges are also altitudes.

Oblique Prisms Prisms in which the lateral faces are not

rectangles (i.e. parallelograms) In this case the lateral edges are not

altitudes.

Naming prisms Most generally prisms are classified by

right or oblique, and then further classified by the shape of the base faces.

The surface area of a solid is measured in square units.

The Lateral Area (L.A.) – of a prism is the sum of the areas of its lateral faces.

The Total Area (T.A.) – is the sum of the areas of all the faces. Sometimes referred to as just Surface Area

B denotes the area of a base (total area or surface area ) T.A. = L.A. + 2B

Total area refers to total surface area.

Theorem L.A. = ah + bh + ch + dh + eh

=(a+b+c+d+e)h =perimeter * h =ph

Find the Surface Area

Find the lateral area, surface area.

Name the prism How many lateral faces Name 2 lateral edges Name an altitude

CD = 7, find the L.A, T.A.

Find the Surface Area using formulas.

Cylinder A solid that has two congruent bases that are both

circles. An altitude of a cylinder is the perpendicular

segment connecting the two circular bases. The height is the length of the altitude, not necessarily a vertical distance.

Find the lateral area Use the lateral area to find the total

area