Please give an example to illustrate how to calculate the area formula and perimeter of a sector.

There are two formulas for the area of a sector: angle system and arc system.

The angle system formula is:

l=n÷360×2πr=nπr÷ 180

Where l is arc length, n is fan-shaped central angle, π is π, and r is base circle radius.

The formula of circular arc system is:

l=|α|×r，

Where l is the arc length, | α| is the absolute value of the radian number of the central angle subtended by the arc L, and r is the radius of the base circle.

Sector perimeter = radius ×2+ arc length, and the formula of sector perimeter is:

c = 2r+(n÷360)πd = 2r+(n÷ 180)πr

Where the radius is r, the diameter is d, and the degree of the central angle subtended by the sector is n.

Extended data:

Other geometric figure area formulas:

The area of a circle is equal to pi times the square of the radius of the circle. Let the radius of a circle be r and the area be s, then the area is s = π R2 (π stands for π).

Area of circular ring: external circular area-internal circular area (πx long radius square -πx short radius square /πx (long radius square-short radius square)).

Let the radius of a circle be r and the area be s, then the area is s = π R2 (π stands for π).

The area formula of any triangle (Helen formula): S2 = p (p-a) (p-b) (p-c), p = (a+b+c) ÷ 2, A, B and C are three sides of the triangle.

Ellipse area formula: S=πab Ellipse area theorem: The area of an ellipse is equal to π times the product of the major semi-axis length (a) and the minor semi-axis length (b) of an ellipse.

References:

Baidu encyclopedia-vermicelli calculation formula