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It is known that the radius of a sector is 6, the central angle is 120 ° and the area and perimeter are calculated
The area is (120 × π × 6 & sup2;) △ 360 = 12 π
The circumference is (120 × π × 6) △ 180 = 4 π
A sector and a circle with an area of 16 π have the same radius. If the central angle of the sector is 45 degrees, what is the arc length to which the central angle of the sector corresponds
Once again, I want to say one side
If you meet my requirements, I will reward you 50 points!
Because the radius is the same
So the diameter is the same
So the ratio of circumference to arc length is equal to the ratio of degrees
Because the area of the circle is 16 π
So the radius is four
So the diameter is 8
The perimeter is 8 π
The ratio of degree is 45: 360 = 1:8
So the ratio of arc length to circumference is 1:8
So the arc length is π
Study hard ^ ^This method is more convenient than the one at the bottom
If the radius of the circle is R and the central angle of the sector is n °, then the sector area s = () and the arc length L = ()
S sector = n π R & # 178 / 360.. L = n π R / 180
If the radius of a circle is 10, what is the arc length and sector area of the center angle of 2
If the radius of the circle is r = 10, what is the arc length C of the center angle a of 2 and the sector area s?
A = 2 radians = 2 * 180 / pi = 114.592 degrees
C=R*A=10*2=20
S=PI*R^2*A/360=PI*10^2*114.592/360=100
The radius of the small circle is 3cm and the radius of the big circle is 4cm______ ．
According to the circumference formula of a circle, the ratio of the circumference of two circles is equal to the ratio of their radii. Because the radius of the small circle is 3cm and the radius of the big circle is 4cm, the ratio of the circumference of the small circle to that of the big circle is 3:4
The circumference of the circle has been increased from 5 factions to 8 factions, and their radius has been increased by several fractions
Increase (8-5) △ 5 = 3 △ 5 = 3 / 5
The circumference of the circle increases from 5 π to 8 π, and its radius increases______ ．
(8 π - 5 π) △ 2 π = 3 π △ 2 π, = 1.5 π. A: its radius is increased by 1.5 π. So the answer is: 1.5 π
When the circumference of a circle increases from 2 π to 5 π, how many times does its radius increase?
The radius increases from 1 to 2.5, (2.5-1) / 1 = 1.5 = 3 / 2, increasing by 3 / 2
The circumference of a circular pool is 18.84 meters. How many square meters is the area?
2, = 3.14 × 32, = 3.14 × 9, = 28.26 square meters. A: its area is 28.26 square meters
There is a ring washer, the circumference of the outer circle is 25.12 cm, the circumference of the inner circle is 15.7 cm, the width of the ring washer
Outer radius = (25.12 / 3.14 / 2 = 4
Inner radius = 15.7 / 3.14 / 2 = 2.5
4-2.5=1.5
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