LESSON Surface Areas Volumes of Spheres 12 6

LESSON Surface Areas & Volumes of Spheres 12 -6 Honors Geometry Warm- Up Today: • Quiz Corrections • 12. 6 Instruction • Homework • Review tomorrow • Quiz Monday

LESSON 12 -6 Surface Areas & Volumes of Spheres 12. 6 Surface Areas and Volumes of Spheres Objective: 1. Find surface areas of spheres. 2. Find volumes of spheres. Vocabulary: great circle, pole, hemisphere

LESSON 12 -6 Surface Areas & Volumes of Spheres sphere – A solid that is bounded by a surface consisting of all points at a given distance from a point constituting its center. A sphere has no lateral edges therefore no lateral area. poles – the endpoints of a diameter of a sphere great circle – the circle that is the cross section of a plane intersects a sphere at the center of the sphere. Ssphere = 4�� r 2 where r is the sphere’s radius r

LESSON 12 -6 Surface Areas & Volumes of Spheres Find the surface area of a sphere with a diameter of 22 garretts. 484�� g 2 If the total area of a sphere is 100�� , find the radius. 5 u A hemisphere is on top of a cylinder which is on top of a cone. Find to the nearest cm 2 the total surface area if the heights and radii of all three are 12 cm. 2449 cm 2

LESSON 12 -6 Surface Areas & Volumes of Spheres The volume of a sphere is equal to four thirds of the product of π and cube of the radius. where r is the radius of the sphere. r

LESSON 12 -6 Surface Areas & Volumes of Spheres Find the volume of sphere with a radius of 3 falanges. V = 36π f 3 Find the volume to nearest tenth of a cubic foot of a sphere if the circumference of the great circle is 10 feet. V ≈ 523. 6 ft 3

LESSON 12 -6 Surface Areas & Volumes of Spheres The ideal ball will usually have between 380 and 432 dimples. These dimples are a half sphere with a diameter of. 16”. If this golf ball has 400 dimples and a diameter of 1. 68”, find the volume of the ball to the nearest thousandths of a cubic inch. 2. 054 in 3

LESSON 12 -6 Surface Areas & Volumes of Spheres Assignment Due tomorrow: • 12. 6 P. 884 #11 -27 odd, 29 -37, 45 – you must show work including formulas! • Quiz 12. 4 -6 on Monday