UNIT 10 – DAY 2ASSIGNMENT

1. Read through and take notes from the following slides

2. Write down any questions you have while reading

• Things you don’t understand• Definitions that sound confusing• etc

3. Write down and attempt to solve each example problem

• Leave yourself room to show work

TODAY’S OBJECTIVE

Students will be able to find the surface area of pyramids and cones

PYRAMID

Definition: A Pyramid is a polyhedron with one polygonal base and triangular lateral faces that meet at a common vertex

The Altitude of a Pyramid (or height) is the perpendicular segment from the vertex to the base.

The SLANT HEIGHT (L) is the length of the altitude of a lateral face of the pyramid

PYRAMID FORMULAS

EX6: FIND LATERAL AND SURFACE AREAS

LA =

SA =

EX 7: FIND LA AND SA

LA =

SA =

CONES

Definition: A cone is like a pyramid but has a circle base. The Altitude (or height) is the perpendicular distance from the vertex to the base. The slant height is the distance from the vertex to a point on the edge of the base.

CONE FORMULAS

EX 8: FIND LA AND SA

LA =

SA =

EX 8: FIND LA AND SA

LA =

SA =

REGULAR TETRAHEDRON• A Tetrahedron is a polyhedron composed

of four congruent, equilateral triangles

SURFACE AREA OF A REGULAR TETRAHEDRON

A Net is a two-dimensional pattern that can be folded into a 3-D figure (We’ll look at more tomorrow)

Lets look at a net for a regular tetrahedron.

How can we find the surface area of a regular tetrahedron?

or

EXAMPLE

Calculate the surface area of a regular tetrahedron with an edge of 5cm

SPHERE

Definition: A Sphere is the set of all points in space equidistant from a given point (the center)

Definition: The Great Circle is the largest cross section (circle) of a sphere and shares the same radius and center as the sphere

Center

Great Circle

SURFACE AREA OF A SPHERE

Find the Surface Area of the following spheres in terms of π

Ex 1: r = 14

Ex 2: d = 12

Ex 3: C = 36π

Ex 4: C = 52π

GOT IT?

Try the Examples!

Write down anything you are confused about!