GEOMETRYToday:

PSAE 12.3 Instruction Practice

Bridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.

Assignment: 12.2 p 732 #29-34,

44, 48, 49

GEOMETRYBridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.

12.3 Surface Area of Pyramids, Cones and Spheres

Objectives: Know the terms for pyramids Find the surface area for pyramids Know the terms for cones Find the surface area for cones Know the terms for spheres Know the surface area for spheres

Vocabulary: pyramid, regular pyramid, cone, sphere, great circle, hemisphere

REMINDER:

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

4 in.

7 in.

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

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

Cone - a circular base and a vertex that is

not in the same plane as the base.

SA of Cone = B + ½Cl where B = Area of Base, C = Circumference and l = slant height of whole figure

What needs to change?

General Formula for SA of Cylinder: SA = 2B + Ch where B = Area of Base,

C = Circumference and h = height of whole figure

hl

5 in

8 in

65π in2

204.1 in2

Find the surface area of the cone.

Ingrid is making a hat for a costume with a diameter of 6½ in and a height of 9¾ in. Find the amount of fabric she will need to cover the hat.

106 in2

Pyramid: a polyhedron with one base and lateral faces that meet at a common vertex.

Lateral faces are always triangles.

In a regular pyramid, the base is a regular polygon and the lateral triangles are congruent.

SA of Regular Pyramid = B + ½Pl where B = Area of Base, P = Perimeter of Base and l = slant height of whole figure

10 cm

12 cm

260 cm2

Find the surface area of the regular pyramid shown.

12.3 Surface Area of Pyramids, Cones and Spheres

Assignment: 12.3 p 738 #1 – 7,

17 – 25 odd Quiz 12.1 – 12.3

Tuesday

Bridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.

GEOMETRYToday:

HW Check 12.3 Instruction Practice

Bridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.

12.3 Surface Area of Pyramids, Cones and Spheres

Assignment: 12.3 p 738 #1 – 7,

17 – 25 odd Quiz 12.1 – 12.3

Tuesday

Bridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.

Homework Quiz

Take out a piece of notebook paper label it CHAPTER 12 HOMEWORK QUIZ.

Write down the date (4/4), then write out p 738 #17, include your picture, work and answer.

12.3 Surface Area of Pyramids, Cones and Spheres

Objectives: Know the terms for pyramids Find the surface area for pyramids Know the terms for cones Find the surface area for cones Know the terms for spheres Know the surface area for spheres

Vocabulary: pyramid, regular pyramid, cone, sphere, great circle, hemisphere

Find the surface area of the regular pyramid shown.

4 ft

9 ft

150 ft2

A gazebo with a square base needs to be glassed in on all sides. If the whole gazebo is 10 feet high and the roof is a 4 foot high square pyramid, find how much glass is needed to cover the gazebo.

240 ft2

Sphere – the locus of points in space that

are equal distance from a point.

Has no base, but can be cut into circles.

Circle at center point called great circle.

SA of Sphere = 4r2 where r = radius.

Find the surface area of a sphere with radius of 2”.

16in2

50.24 in2

2”

Find the surface area of the hemisphere of the above figure.Cut in half? 8in2?

12in2

37.68 in2

Formulas You Should KnowS = 2B + PhS = 2B + ChS = B + ½PlS = B + ½ClS = 4r2

Only 3 ReallyS = 2B + PhS = B + ½PlS = 4r2

12.3 Surface Area of Pyramids, Cones and Spheres

Assignment: 12.3 p 739 #26-34

Even, 44-46 Quiz 12.1 – 12.3

Tuesday

Bridge Tips:

Measure the wood used on your sketch before you start cutting and gluing.