GEOMETRY Today: 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 GEOMETRY Bridge 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. 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 + ½C l 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 h l

5 in 8 in 65π in in 2 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 in 2

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

10 cm 12 cm 260 cm 2 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.

GEOMETRY Today: 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 ft 2

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 ft 2

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 = 4  r 2 where r = radius.

Find the surface area of a sphere with radius of 2”. 16  in 2  in 2 2” Find the surface area of the hemisphere of the above figure. Cut in half? 8  in 2 ? 12  in 2  in 2

Formulas You Should Know S = 2B + Ph S = 2B + Ch S = B + ½P l S = B + ½C l S = 4  r 2 Only 3 Really S = 2B + Ph S = B + ½P l S = 4  r 2

12.3 Surface Area of Pyramids, Cones and Spheres Assignment:  12.3 p 739 #26-34 Even,  Quiz 12.1 – 12.3 Tuesday Bridge Tips: Measure the wood used on your sketch before you start cutting and gluing.