相似三角形--水

使用long long

Time Limit:500MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu

Submit  Status  Practice  LightOJ 1043  uDebug

Description

See the picture below.

You are given AB, AC and BC. DE is parallel to BC. You are also given the area ratio between ADE and BDEC. You have to find the value ofAD.

Input

Input starts with an integer T (≤ 25), denoting the number of test cases.

Each case begins with four real numbers denoting AB, AC, BC and the ratio of ADE and BDEC (ADE / BDEC). You can safely assume that the given triangle is a valid triangle with positive area.

Output

For each case of input you have to print the case number and AD. Errors less than 10^-6 will be ignored.

Sample Input

4

100 100 100 2

10 12 14 1

7 8 9 10

8.134 9.098 7.123 5.10

Sample Output

Case 1: 81.6496580

Case 2: 7.07106781

Case 3: 6.6742381247

Case 4: 7.437454786

题解：相似三角形面积比比等于长度比的平方

当时没做出来，只因为把面积比看成了边的长度比，似不似傻，总是想那么复杂

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#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
double a,b,c,d;
int main()
{
int t;
int k=1;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%lf%lf%lf%lf",&a,&b,&c,&d);
		double ans=a*sqrt(d/(d+1)*1.0);
		printf("Case %d: ",k++);
		printf("%.7lf\n",ans);
	}
	 
	return 0;
}