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Learn about Cavalieri's Principle and apply formulas to calculate volumes and surface areas of prisms and cylinders in geometry class today. Explore cross-sections, bases, and heights of various solids to find their volumes accurately. Practice with assigned homework and review materials.
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Today’s Class: Problem of the Day Cavalieri’s Principle Volume of a Prism Volume of a Cylinder HW: Pg.513, Q7-20
Problem of the Day Formulae: LA = p • h TSA = LA +2B Area of B = ½ap 10 • Find • The Lateral Surface Area • The Total Surface Area 3 5
h h Cavalieri’s Principle If 2 solids have the same vertical height, and if the cross sections formed by every plane parallel to the bases of both solids have equal areas, then the 2 solids have the same volume.
Volume? 2 3 6
Volume of Rectangular Prism Area of Base x height = length x width x height B h = l w h h w l
Any Prism V = B h 3 4 B = ½ (3 x 4) = 6 h = 3 V = 6 (3) = 18 3 5
Volume? V = B h = (2 x 4) x (3) = 24 = (2 x 3) x (4) = 24 = (3 x 4) x (2) = 24 3 2 4
Volume? 15 9 12
Volume? Bases are Isosceles trapezoids 2 B = ½ (4) (2 + 8) = 20 h = 3 V = 20 (3) = 60 5 3 4 8
Volume of Cylinder V = B h B = r2 V = r2 h Not same as prism! height radius Volume = (area of Base) x height same as prism!
Area and Volume? TA = LA + 2B LA = 2 r h = 2 (4) (8) = 64 B = r2 = 16 TA = 64 + 32 = 96 V = B h = 16 (8) = 128 8 r = 4
Volume? 2 2 ½
Find the volume: Formulae: V = B • h Area of B = ½ap 10 3 5
Today’s Class: • Problem of the Day • Review Slides • Worksheet HW: Finish Review Worksheet
Problem of the Day: Find the Total Surface Area AND the volume 9 6 25