The sector of a circle is just like a piece of a circle which is covered by a curve (arc) and two straight lines (radii). The curve or an arc is a part of the circumference of the circle. The important and necessary condition for the sector of the circle is that these two lines must be the radius of a circle r. The jointing point of these two radii is the centre of the circle and they make a angle β, β is called by central angle. When we make a sector of a circle then another one is automatically observed. The circle is divided in two sectors and these are minor sector and major sector. M is the length of the arc of the minor sector.
When the value of the β or central angle is 180 degree the circle is called semicircle.
When the value of the β or central angle is 90 degree the sector is called quadrants.
When the value of the β or central angle is 60 degree the sector is called sextants.
When the value of the β or central angle is 45 degree the sector is called octants.
When we form an angle connecting the end point of the arc to any point in circumference except in sector is half of the angle made by the sector at the center.
To find parameter (P) of the sector is adding length (L) of arc plus two times radii.
P = L + 2r
For finding the total surface area of the sector we have to know first area of circle so area of circle is pie r2 so, we multiply the area of circle by the ratio of sector angle by circle angle therefore area of a sector will be r2β/2 where β is a central angle. The sector of a circle and the product rule are described in the CBSE class 9 previous year question papers.
When the value of the β or central angle is 180 degree the circle is called semicircle.
When the value of the β or central angle is 90 degree the sector is called quadrants.
When the value of the β or central angle is 60 degree the sector is called sextants.
When the value of the β or central angle is 45 degree the sector is called octants.
When we form an angle connecting the end point of the arc to any point in circumference except in sector is half of the angle made by the sector at the center.
To find parameter (P) of the sector is adding length (L) of arc plus two times radii.
P = L + 2r
For finding the total surface area of the sector we have to know first area of circle so area of circle is pie r2 so, we multiply the area of circle by the ratio of sector angle by circle angle therefore area of a sector will be r2β/2 where β is a central angle. The sector of a circle and the product rule are described in the CBSE class 9 previous year question papers.
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