 Geometry help please? - XP Math - Forums Sign Up FREE! | Sign In | Classroom Setup | Common Core Alignment  XP Math - Forums Geometry help please? 07-27-2007 #1 Halley Guest   Posts: n/a Geometry help please? 1) Area = 3024 sq. cm; h = 36 cm ; a = 78 cm ; b = ___2) The area of the sector is 108 pie sq. cm. Measure of FAN = ___3) HELP is a rectangle. All measurements are in cms. Area of shaded region = ___Here is a link to pictures of the problems:http://farm2.static.flickr.com/1006/...72de59d9_o.jpg 07-27-2007 #2 Clov Guest   Posts: n/a 1. 3024= 1/2 ( 36) ( 78 +b) b= 3024*2/36 - 78 = 902. 108 pie = 1/2 ( 18)^2 ( angle) angle = 2/3 pie. measure of FAN = 18+18+ 18( 2/3 pie) = 36 + 12 pie = 36+37.71 = 73.71 cm3.area of rectangle = 14( 14+14) = 392 cm sq area of 2 circle = 2[ 1/2 ( 7)(7)( 2 pie rad) =308 cm area of shaded region = 392-308 = 84cm sq 07-27-2007 #3 No.1 Quarterback Guest   Posts: n/a okay I can solve question 3 area of thriangle is pie r sq so you go pie 7 sq and because there is 2 triangles you times answer by 2 which equals 307.88.then you work out the area of the rectangle which is 14 times 28 which equals 392finally you go 392-307.88 which equals 84.12cm sq which is the shaded part. hope that helps hey by the way put me on you contacts and i will help you with some more problems 07-27-2007 #4 bigcha Guest   Posts: n/a 1) The area of a trapezoid is found by taking the average of the two bases, top and bottom (called the midsegment) and multiplying by the height h: [(a + b) / 2] X h = Area ; so [(78 + b) / 2] X 36 = 3024 and b = 90 cm2) FAN is called a central angle (CA) and has the same measure in degrees of the arc above it. We find the measure of a sector by finding first the area of the entire circle, then multiplying by the fraction we want, which is the CA / 360 (central angle / entire circle) pi X 18^2) X (CA / 360) = 108 X pi so CA = 120 (degrees)3) These kind of area problems always need a plan, so here it is: find the area of the rectangle first, then subtract the area of the circles. I hope it's obvious that the width of the rectangle is the same as the diameter of the circle (14) and the length is two diameters (28). The radius of both circles is the same, 7. So: (area of rectangle) - (2 X area of circle) and (14 X 28) - (2 X [7^2 X pi]) = shaded region 392 - 98 pi or 84.28 using 3.14 for pi

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