Sector area formula: the sector area is equal to the area of the circle multiplied by the ratio of radian angle and 2π (because the sector area is proportional to its angle, and 2π is the angle of the whole circle), and S=π*r*r*(θ/2*π)=r*r*θ/2(S: indicates the sector area, r: indicates the radius of the circle, and θ: indicates the sector.
Extended data:
The side development diagram of the cone is a fan, the radius of which is the waist line length of the cone, and the arc length is the circumference of the bottom surface.
Sector arc length formula:
L=r*θ(L: indicates the arc length of the sector, θ: indicates the radian, and r: indicates the radius of the circle corresponding to the sector).
If an angle is given, then:
L=r* (angle /2*π).
Conversion of sector radian and angle;
If the given quantity in the sector is an angle instead of an radian, then the conversion formula of radian and angle is that radian is equal to angle divided by 2 times π, that is, θ = (angle) /2*π.
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