八边形公式
几何是关于形状研究的数学分支。形状的类别分为两种,即。平面形状和实体形状。几何通过给出标准公式来研究这些形状的面积、周长、体积和其他参数。
这篇文章解释了八边形公式,它给出了八边形的面积和周长的公式。它还包含示例数值问题,以便更好地理解。
八角形
八边形是具有八个边和八个角的平面形状。它是一个八边形的正多边形。八边形的每个内角为 135°,八边形的所有内角之和等于 108°。同样,八边形的外角是45度,所有外角的和等于360度。
八边形由 20 条在图形中心相交的对角线组成。所有这些对角线都具有相同的长度。
八角公式
该几何提供了用于计算正八边形的周长、面积和对角线的单独派生公式。八边形的周长、面积和对角线公式统称为八边形公式。
要找到八边形的对角线数,我们使用给定的公式。
对角线数 = n(n – 3)/2
8(8 – 3)/2
20
其中 s 表示边长
并且,n表示边数
一个正多边形通常由 20 条对角线组成。因此,八边形公式主要用于计算八边形的面积和周长。这些计算是通过使用八边形的边长来进行的。
八边形的面积公式由下式给出
八边形面积(A) = 2s 2 (1 + √2)
其中 s 是边长
八边形的周长公式由下式给出,
八边形的周长(P) = 8s
其中 s 是边长。
示例问题
问题1:使用八边形公式求边长为2cm的八边形的面积和周长。
解决方案:
Given:
length of a side of the octagon is 2cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(2)2(1 + √2)
A = 19.31cm2
By using the octagon formula for the perimeter,
Perimeter of the octagon (P) = 8s
P = 8 × 2
P = 16cm
Hence, the area and perimeter of the given octagon are 19.31cm2 and 16cm respectively.
问题2:使用八边形公式求边长为4cm的八边形的面积和周长。
解决方案:
Given:
length of a side of the octagon is 4cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(4)2(1 + √2)
A = 77.25cm2
By using the octagon formula for the perimeter
The perimeter of the octagon (P) = 8s
P = 8 × 4
P = 32cm
Hence, the area and perimeter of the given octagon are 77.25cm2 and 32cm respectively.
问题3:使用八边形公式求边长为2.5cm的八边形的面积和周长。
解决方案:
Given:
length of a side of the octagon is 2.5cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(2.5)2(1 + √2)
A = 30.17cm2
By using the octagon formula for the perimeter
The perimeter of the octagon (P)=8s
P = 8 × 2.5
P = 20cm
Hence, the area and perimeter of the given octagon are 30.17cm2 and 20cm respectively.
问题 4:给出一个周长为 32 厘米的正八边形。用八边形公式求它的面积。
解决方案:
Given:
The perimeter of the octagon is 32cm.
The perimeter of the octagon(P) = 8s
32 = 8s
s = 4cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(4)2(1 + √2)
A = 77.25cm2
问题 5:给出一个周长为 48 厘米的正八边形。用八边形公式求它的面积。
解决方案:
Given:
The perimeter of the octagon is 48cm.
The perimeter of the octagon(P) = 8s
48 = 8s
s = 6cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(6)2(1 + √2)
A = 173.82cm2
问题6:如果给出一个八边形的周长等于40cm。计算给定八边形的面积。
解决方案:
Given:
The perimeter of the octagon is 40cm.
The perimeter of the octagon(P) = 8s
40 = 8s
s = 5cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(5)2(1 + √2)
A = 120.71cm2
问题7:如果给定一个长度为3cm的八边形,它的面积和周长是用八边形公式计算的吗?
解决方案:
Given:
The side of the octagon is 3cm
By using the octagon formula for the area
Area of octagon(A) = 2s2(1 + √2)
A = 2(3)2(1 + √2)
A = 43.45cm2
By using the octagon formula for the perimeter
The perimeter of the octagon (P) = 8s
P = 8 × 3
P = 24cm
Hence, the area and perimeter of the given octagon are 43.45cm2 and 24cm respectively.