What is the formula for the circumference and area of a semicircle?

The formula for the circumference of a semicircle is: c= r+2r( isPiwhere r is the radius of the circle); The formula for the circumference of a circle is: c=2 r= d.

Circumference formula for a semicircle:

c=πr+2r

2 Formula for the area of a semicircle:

s=1/2πr2

1. The area of the semicircle: s semicircle = (r 2) 2. (r is the radius).

2. The area of the ring: S big circle - S small circle = (r 2-r 2) (r is the radius of the large circle, r is the radius of the small circle).

3. The circumference of the circle: c=2 r or c=d. (d is the diameter, r is the radius).

4. The circumference of the semicircle: d+(d) 2 or d+ r. (d is the diameter, r is the radius).

5. The fan arc is long.

l = central angle.

radian system) r = n r 180 ( is the central angle of the circle) (r is the radius of the fan).

Circumference formula for a semicircle:

A semicircle is a figure surrounded by curves, it is half of a circle, and the position of the center of the semicircle is the position of the center of its concentric circles, which has only one diameter, but has an infinite radius, and has an axis of symmetry.

The circumference formula of a semicircle = pi radius + diameter.

It is represented by a letter formula as:

c half = r + 2r (d).

The area of the semicircle.

s semicircle = (r 2) 2. (r is the radius).

The analysis process is as follows:

1) Assuming that the radius of the semicircle is r, then according to the formula for calculating the area of the circle, the area of the circle of radius r = r2.

2) The semicircle is half of the circle, so the area of the semicircle = r2 2.

Circumference: c = 2 r (r radius).

Area: s = r

Circumference of a semicircle: c = r + 2r

Semi-circular area. s=πr²/2

Circumference of a semicircle = circumference of a circle 2 + diameter of a circle, the formula is r+2r. Semicircle area = circle area 2= r 2

In the study of mathematics in the beginning of the dispersion, circles and semicircles are very common figures, and I have sorted out their perimeter formulas and area formulas.

Let's take a look at it with me.

c=2πrs=（πr2

c=πr+2r

s=（πr2

s=4πr2

v=（4/3)πr^3

The formula for the area of a semicircle is: s = rr 2 ( square of radius 2).

The formula for the circumference of a semicircle is: c = r + 2r (radius + diameter).

The formula for the area of a semicircle is, s= r 2 2

The formula for the circumference of a semicircle is, c= r+2r

A semicircle, the area is equal to the square of the radius multiplied by the radius, divided by two.

The formula for the area of a semicircle is: the square of the radius of the vultures divided by two.

丌 multiply the square of r by 2 (area).

Circumference: c = 2 r (r radius).

Area: s = r

Circumference of a semicircle: c = r + 2r

Semicircular area: s = r 2

Standard equation for a circle: In a planar Cartesian coordinate system, the standard equation for a circle with the point o(a,b) as the center and r as the radius is (x-a) 2+(y-b) 2=r 2.

General equation of the circle: After moving the standard equation of the circle and merging the similar terms, the general equation of the circle is x 2 + y 2 + dx + ey + f = 0. Compared with the standard equation, in fact, d = -2a, e = -2b, f = a 2 + b 2.

The positional relationship between the circle and the point: take the point p and the circle o as an example (let p be a point, then po is the distance from the point to the center of the circle), p is outside o, po r; p on o, po r; p in o, po r.

There are 3 positional relationships between lines and circles:

No common point is separated;

There are two common points that intersect;

A circle and a straight line have a single common point that is tangent, this straight line is called the tangent of the circle, and this only common point is called the tangent point.

Take the straight line ab and the circle o as an example (let op ab be in p, then po is the distance from ab to the center of the circle):

ab and o are separated, po r; ab is tangent to o, po r; ab intersects o and po r.

There are 5 positional relationships between two circles: if there is no common point, one circle is called alienation outside the other circle, and it is called containment within it; If there is a single common point, a circle outside another circle is called an external incision, and an internal incision is called an internal incision; There are two common points called intersection. The distance between the centers of two circles is called the center distance.

The radii of the two circles are r and r, and r r, and the center distance of the circle is p: outward p r+r; Exentom p=r+r; intersecting r-r p r+r; incision p=r-r; Contains p r-r.

The formula for the area of a semicircle is: s = rr 2 ( square of radius 2).The formula for the circumference of a semicircle is: c = r + 2r (radius + diameter).

In the same circle or equal circle, if one set of quantities in two central angles, two circumferential angles, two sets of arcs, two strings, and two chord center distances are equal, then the rest of the groups of quantities corresponding to them are equal.

In an identical or equal circle, the circumferential angle of an equal arc is equal to half of the central angle of the circle to which it is opposite (the circumferential angle is on the same side as the central angle of the chord). If an arc is twice as long as another arc, then the circumferential and central angles of the arc are twice as long as the other arc. The area of the semicircle.

s semicircle = (r 2) 2, r is the radius. The circumference of the semicircle: d+(d)2 or d+ is the diameter, and r is the radius.

The formula for the circumference of a semicircle is the circumference multiplied by the radius, i.e., c= r. The semicircle area formula is half of the square of the radius multiplied by the radius i.e., s = r 2.

1) The formula for the circumference of a circle.

The circumference of the circle: c=2 r=c= d

The circumference of the semicircle = half of the circumference of the circle c= r

2) The area formula of the circle.

The formula for calculating the area of a circle: s= r

Divide the circle into equal parts, which can be put together into an approximate rectangle. The width of the rectangle is equal to the radius of the circle.

Pi is the ratio of the circumference of a circle to its diameter, generally represented by Greek letters, and is a mathematical constant that is prevalent in mathematics and physics. It is also equal to the ratio of the area of the circle to the square of the radius. It is the key value to accurately calculate the geometric shape of the circumference, area of the circle, and the volume of the sphere.

In analytics, it can be strictly defined as the smallest positive real number x satisfying sinx=0.