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!
