# Angle between two Planes in 3D in C Program?

CServer Side ProgrammingProgramming

Here we will see how to calculate the angle between two planes in the three dimensional space. The planes are P1 and P2. The equations of Pi like below −

If the angle is ‘A’, then it will follow this rule −

## Example

#include <iostream>
#include <cmath>
using namespace std;
class Plane{
private:
double a, b, c, d;
public:
Plane(double a = 0, double b = 0, double c = 0, double d = 0){
this->a = a;
this->b = b;
this->c = c;
this->d = d;
}
double friend angle(Plane p1, Plane p2);
};
double angle(Plane p1, Plane p2){
double nume = (p1.a * p2.a) + (p1.b * p2.b) + (p1.c * p2.c);
double deno1 = (p1.a * p1.a) + (p1.b * p1.b) + (p1.c * p1.c);
double deno2 = (p2.a * p2.a) + (p2.b * p2.b) + (p2.c * p2.c);
return (180.0 / 3.14159) * acos(nume/ (sqrt(deno1) * sqrt(deno2)));
}
int main() {
Plane p1(2.0, 2.0, -3.0, -5.0), p2(3.0, -3.0, 5.0, -6.0);
cout << "Angle: " << angle(p1, p2) << " degree";
}

## Output

Angle: 123.697 degree
Published on 20-Aug-2019 11:38:12