LEARN FORMULAS FOR DIFFERENT POLYGONS: PART 2
 CIRCLE Learn some parts of a circle and formulae   Before we learn formulas for finding areas and circumference of circles, let’s discuss the following: Consider the circle below:   Radius is a straight line from the center to any point on the circumference of a circle or sphere. From the illustration above: the Radius is the line segment CO   Diameter: is a straight line joining two points on the circumference and passing through the centre. From the illustration above: the Diameter is the line segment AB   Chord: is any straight line joining two points on the circumference. From the illustration above: the Chord is the line segment DE Note: A diameter is a chord passing through the centre.   A sector: is a portion of a circle enclosed by two radii. From the illustration above: the Sector is the figure AOC   An arc: is a connected section of the circumference of a circle. From the illustration above: the arcs are AC, CB, BE, ED and DA   A segment is a portion of a circle enclosed by a chord.     FORMULAE   Circle: Area = πr2 which means (π x r x r) Circumference = πD which means π x D   Semi Circle: Area = 1/2 πr2 which means (1/2 x π x r x r) Circumference = 1/2 πD + D   Three quarter circle Area = 3/4 πr2 which means (3/4 x π x r x r) Circumference = 3/4 πD + D   Quarter circle: Area = 1/4 πr2 which means (1/4 x π x r x r) Circumference = 1/4 πD + D   Sector: Area = θ/360 πr2 which means ( θ/360 x π x r x r) Circumference = θ/360 πD + D   Circle with given angle: Area = θ/360 πr2 which means ( θ/360 x π x r x r) Circumference = θ/360 πD + D   ************* END ******************** .u-star-rating-16 { list-style:none;margin:0px;padding:0px;width:80px;height:16px;position:relative;background: url('/.s/t/1706/rating.png') top left repeat-x } .u-star-rating-16 li{ padding:0px;margin:0px;float:left } .u-star-rating-16 li a { display:block;width:16px;height: 16px;line-height:16px;text-decoration:none;text-indent:-9000px;z-index:20;position:absolute;padding: 0px;overflow:hidden } .u-star-rating-16 li a:hover { background: url('/.s/t/1706/rating.png') left center;z-index:2;left:0px;border:none } .u-star-rating-16 a.u-one-star { left:0px } .u-star-rating-16 a.u-one-star:hover { width:16px } .u-star-rating-16 a.u-two-stars { left:16px } .u-star-rating-16 a.u-two-stars:hover { width:32px } .u-star-rating-16 a.u-three-stars { left:32px } .u-star-rating-16 a.u-three-stars:hover { width:48px } .u-star-rating-16 a.u-four-stars { left:48px } .u-star-rating-16 a.u-four-stars:hover { width:64px } .u-star-rating-16 a.u-five-stars { left:64px } .u-star-rating-16 a.u-five-stars:hover { width:80px } .u-star-rating-16 li.u-current-rating { top:0 !important; left:0 !important;margin:0 !important;padding:0 !important;outline:none;background: url('/.s/t/1706/rating.png') left bottom;position: absolute;height:16px !important;line-height:16px !important;display:block;text-indent:-9000px;z-index:1 } Category: Upper Primary | Added by: Admin (07/Apr/2017) | Author: Yahya Mohamed (Badshah) E W Views: 312 | Rating: 0.0/0