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GEOMETRY. Today: PSAE 12.3 Instruction Practice. Bridge Tips: Measure the wood used on your sketch before you start cutting and gluing. GEOMETRY. Assignment: 12.2 p 732 #29-34, 44, 48, 49. Bridge Tips: Measure the wood used on your sketch before you start cutting and gluing.
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GEOMETRY Today: • PSAE • 12.3 Instruction • Practice Bridge Tips: Measure the wood used on your sketch before you start cutting and gluing.
GEOMETRY Assignment: • 12.2 p 732 #29-34, 44, 48, 49 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 + Phwhere B = Area of Base, P = Perimeter of Base andh = height of whole figure General Formula for Surface Area Cylinder: SA = 2B + Chwhere B = Area of Base, C = Circumference andh = 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+ ½Clwhere B = Area of Base, C = Circumference andl= slant height of whole figure General Formula for SA of Cylinder: SA = 2B + Chwhere B = Area of Base, C = Circumference and h = height of whole figure l h What needs to change?
Find the surface area of the cone. 8 in 65π in2 204.1 in2 5 in
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+ ½Plwhere B = Area of Base, P = Perimeter of Base andl= slant height of whole figure
12 cm 10 cm Find the surface area of the regular pyramid shown. 260 cm2
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. 150 ft2 9 ft 4 ft
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 = 4pr2 where r = radius.
Find the surface area of a sphere with radius of 2”. 2” 16p in2 » 50.24 in2 Find the surface area of the hemisphere of the above figure. Cut in half? 8p in2? 12p in2 » 37.68 in2
Formulas You Should Know S = 2B + Ph S = 2B + Ch S = B + ½Pl S = B + ½Cl S = 4pr2 Only 3 Really S = 2B + Ph S = B + ½Pl S = 4pr2
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.