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If the area of a sector is 5 / 11 of the area of its circle, what is the arc length of the sector?
5 out of 11,
The arc length of the sector is 2 π N R / 360 (n is the degree of the center angle, R is the radius)
The area of the sector is π N R ^ 2 / 360 (n is the degree of the center angle, R is the radius)
When n = 360 degrees, it is the circumference and area of the circle
The area of a sector is 1 / 5 of the area of a circle with the same radius, and the length of the arc contained in the sector is a fraction of the circumference of the circle with the same radius
Sector area = (1 / 2) sector arc length * radius = (1 / 5) pi * radius ^ 2
Sector arc length / radius = 2pi / 5
Sector arc length / circumference = (sector arc length / radius) / (2pi) = 1 / 5
The length of an arc is four seventh of its far perimeter. What is the sector area of the arc?
The length of an arc is four seventh of its far perimeter, and the sector area of the arc is four seventh of the circle area
The area of the sector is 10 square meters, the area of the circle is 30 square meters, and the arc length of the sector is a fraction of the circumference of the circle?
1/3
The area of the sector is s. if the central angle of the circle remains unchanged and the perimeter of the sector is expanded by 2 times, then the area of the sector is?
The formula
Double or double?
In the latter case:
S=(R*R*theta)/2
l=2R+R*theta=R*(2+theta)
If theta is not changed, l -- > L * 2, then R -- > R * 2 is obtained by substituting S-form
S is proportional to the square of L
If the area ratio of the two circles is 9:1 and the circumference difference is 12.56 cm, how many square centimeters is the area difference between the two circles?
If the area ratio of the two circles is 9:1, the perimeter ratio is 3:1
12.56 × 1 / (3-1) = 6.28 cm small circumference
The radius of the small circle is:
6.28 ﹣ 3.14 ﹣ 2 = 1cm
The area of small circle is: 3.14 × 1 & # 178; = 3.14 square centimeter
The large circle has more area than the small circle: 3.14 × (9-1) = 25.12 square centimeters
How many roses can be planted around a circular flower bed with a circumference of 18 meters. One rose should be planted every 60 cm?
18m = 1800
1800 divided by 60 = 30
A flower bed with a circumference of 62.8 meters is divided into five sectors, and one of them is planted with rose. How large is the planting area of rose?
The fragrance, the fragrance,
3.14 × (62.8 ﹣ 3.14 ﹣ 2) & ﹣ 178; ﹣ 5 = 62.8 (M2)
The perimeter of a round flower bed is about 62.8 meters. How many square meters is the area of this flower bed?
The radius of flower bed: 62.8 ÷ (2 × 3.14) = 62.8 ÷ 6.28 = 10 (m) the area of flower bed: 3.14 × 102 = 314 (M2) a: the area of flower bed is 314 m2
Hope primary school playground has a round altar, the perimeter of the flower bed is 62.8 meters, the flower bed area is how many square meters?
This is the third question on page 10 of mathematical knowledge and ability training
62.8 ÷ 3.14 = 20 (M & sup2;) [calculate diameter]
20 △ 2 = 10 (m)
10 & sup2; × 3.14 = 314 (M & sup2;) [calculate area]
A: this flower bed covers an area of 314 square meters
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