If the radius of a circle is r, the area of a sector can be obtained

If the radius of a circle is r, the area of a sector can be obtained

πr²/2

The perimeter of a sector is 6cm. If the sector has the largest area, the radius of the sector should be 6cm

This is a relatively simple mathematical problem
According to the formula of sector perimeter: C = 6 = 2R + θ R
Sum area formula: S = 1 / 2 θ R * r
We can get the equation: S = (6-2r) * r
∵ largest area
∴r＝1.5㎝
I'm a relative of angel. I wish you an early solution,

Calculate the sector area when the sector arc length is 18cm and the radius is 12cm

S = RL / 2 = 108CM square
L arc length, R radius

1. Given the radius of the circle is 0.5m, find the arc length of 3rad center angle. 2. The arc length of the sector is 18cm, the radius is 12cm, find the area of the sector
3. After 1 hour and 15 minutes, how many degrees did the hour hand and minute hand turn? How many radians did they equal

The arc length of 1.3rad central angle is 0.5 * 3 = 1.5m
2. The area of the sector is 1 / 2 * 12 * 15 = 90cm;
3. Turn clockwise 0.5 * (1 * 60 + 15) = 37.5 ° = 5 / 24 π
Minute hand rotation 6 * (1 * 60 + 15) = 450 ° = 5 / 2 π

In a circle with a radius of 6cm, the arc length of 60 ° is equal to______ Cm (the result is retained π)

The arc length is 60 π × 6180 = 2 π, so the answer is 2 π

A chord of a circle is equal to the radius, and the angle of the center of the circle to which this chord is directed is______ Degree

If the radius is r, then the chord length is R. by two radii, the chord can form an equilateral triangle, and its inner angle is 60 degrees. Therefore, the degree of the central angle of the chord is 60 degrees. Therefore, the answer is 60

If the chord length of a circle is equal to the radius of the circle, what is the central angle of the circle?

If the chord length L of the circle is equal to the radius r of the circle, what is the center angle a of the circle?
A=2*ARC SIN((L/2)/R)
=2*ARC SIN((R/2)/R)
=2*ARC SIN(0.5)
=60 degrees

In ⊙ o, AB is the diameter, the chord center distance of AC is 3, then the length of BC is______ ．

∵ AB is the diameter, ∵ C = 90 °, ∵ of ⊥ AC, ∵ AFO = 90 °, ∵ of ∥ BC, ∵ o is the center of the circle, ∵ Ao = ob, ∵ of = 12bc, ∵ of = 3, ∥ BC = 6

Given that in circle O, AB is the diameter, BC = 4 √ 3cm, then the chord center distance of chord AC is?

2 √ 3cm prove: through o point do OE vertical CB to e of vertical AC to f connect OC, then OC = ob (all radius) because AB is diameter, so ∠ ACB = 90 ° and ∠ OFC = ∠ OEC = 90 ° so quadrilateral office is rectangular, so CE = of
Because OC = ob OE vertical CB, so CE = EB = CB / 2 = 2 √ 3cm, so of = 2 √ 3cm, that is, the chord center distance of chord AC is 2 √ 3cm

Given that the diameter of circle O AB = 6cm, the angle between chord AC and ab is 30 °, find the length of chord BC and the chord center distance of chord BC