Geometry 20/21 March 2013

Warm UpA sphere has a surface area of 16π cm2. The volume of the sphere is:a. 8π/3 cm3

b. 32π/3 cm3

c. 64π/3 cm3

d. 256π/3 cm3

objective

Students will apply the formulas for volume and surface area of a sphere to solve problems.

Students will take notes, do problems using think-pair-share and present their work to the class.

Surface AreaSurface AreaIn general,

SA = ASA = Abase(s)base(s) + A + Asidessides

SASAprismsprisms = A = Abases bases + PH+ PH where P = perimeter and H = height of prismwhere P = perimeter and H = height of prism

SaSacone cone = = ππrr22 + + ππrlrlwhere l is slant heightwhere l is slant height

Volume FormulasVolume Formulas

Prism/CylinderPrism/Cylinder

baseV A H

Cone/pyramidCone/pyramid (pointy (pointy things)things)

3baseA H

V

SphereSphere34

3

rV

Surface area Surface area of a Sphereof a Sphere

24SA r

Volume applications:

If the ice cream formed a sphere with radius of

8 cm, and the 5 inch high cone was filled

with ice cream, what is the total volume of ice

cream in this tasty dessert?

A dump truck is unloading sand

which is falling into a conical pile. Find

the height of the cone when the

diameter of the pile is 24 ft and the

volume of the sand is 600 cubic feet.

Round your answer to nearest tenth.

practice1) Page 466: 1 – 8 SA and VOLUME1) Page 466: 1 – 8 SA and VOLUMEOdd Tables: #9 Even Tables: #10Odd Tables: #9 Even Tables: #102) page 559: 1 – 5 SA and VOLUME2) page 559: 1 – 5 SA and VOLUME3) Find the Vol and SA of a regular hexagonal pyramid with height 8 cm, 6 cm sides.Be ready to share your work with the class.

Debrief

What do you need to study for the test?What is easy?What is still confusing?