给定半径的两个圆,使两个圆彼此不接触。任务是找到圆心与两个横向公切线与圆的交点的距离之比。
例子:
Input :r1 = 4, r2 = 8
Output :1:2
Input :r1 = 5, r2 = 13
Output :5:13
方法:
- 令圆的半径分别为r1 & r2和C1 & C2 。
- 令P为两个横向公切线与圆的交点,而A1和A2为切线与圆的接触点。
- 在三角形PC1A1和三角形PC2A2中,
角C1A1P =角C2A2P = 90度{将圆心与接触点连接的线与切线成90度角},
同样,角度A1PC1 =角度A2PC2 {垂直相反的角度始终相等}
因此,角度A1C1P =角度A2C2P
因为角度相同,所以三角形PC1A1和PC2A2相似。 - 因此,由于三角形的相似性,
C1P / C2P = C1A1 / C2A2 = r1 / r2
C++
// C++ program to find the ratio
// of the distance between the centres of the circles
// and the point of intersection
// of two transverse common tangents
// to the circles which do not touch each other
#include
using namespace std;
int GCD(int a, int b)
{
return (b != 0 ? GCD(b, a % b) : a);
}
// Function to find the ratio
void ratiotang(int r1, int r2)
{
cout << "The ratio is "
<< r1 / GCD(r1, r2)
<< ":"
<< r2 / GCD(r1, r2)
<< endl;
}
// Driver code
int main()
{
int r1 = 4, r2 = 8;
ratiotang(r1, r2);
return 0;
}
Java
// Java program to find the ratio
// of the distance between the centres of the circles
// and the point of intersection
// of two transverse common tangents
// to the circles which do not touch each other
import java.io.*;
class GFG{
static int GCD(int a, int b)
{
return (b != 0 ? GCD(b, a % b) : a);
}
// Function to find the ratio
static void ratiotang(int r1, int r2)
{
System.out.println("The ratio is "
+ r1 / GCD(r1, r2)
+ ":"
+ r2 / GCD(r1, r2));
}
// Driver code
public static void main (String[] args)
{
int r1 = 4, r2 = 8;
ratiotang(r1, r2);
}
}
// This code is contributed by NamrataSrivastava1
Python
# Python3 program to find the ratio
# of the distance between the centres of the circles
# and the point of intersection
# of two transverse common tangents
# to the circles which do not touch each other
def GCD(a, b):
if(b!=0):
return GCD(b, a%b);
else:
return a;
# Function to find the ratio
def ratiotang(r1, r2):
print("The ratio is", r1 // GCD(r1, r2),
":", r2 // GCD(r1, r2));
# Driver code
r1 = 4; r2 = 8;
ratiotang(r1, r2);
# This code is contributed by Code_Mech
C#
// C# program to find the ratio
// of the distance between the centres of the circles
// and the point of intersection
// of two transverse common tangents
// to the circles which do not touch each other
using System;
class GFG
{
static int GCD(int a, int b)
{
return (b != 0 ? GCD(b, a % b) : a);
}
// Function to find the ratio
static void ratiotang(int r1, int r2)
{
Console.WriteLine("The ratio is "
+ r1 / GCD(r1, r2)
+ ":"
+ r2 / GCD(r1, r2));
}
// Driver code
static public void Main ()
{
int r1 = 4, r2 = 8;
ratiotang(r1, r2);
}
}
// This code is contributed by Tushil.
PHP
Javascript
输出:
The ratio is 1:2