# Program to calculate area and perimeter of equilateral triangle

An equilateral triangle is a triangle in which all three sides and angles are equal. All three internal angles of equilateral triangle measures 60 degree.

- If we know the length of each sides of equilateral triangle, then we can use below mentioned formula to calculate area of equilateral triangle.
Area of Equilateral Triangle = (sqrt(3)/4) * a * a

- If we know the length of altitude of equilateral triangle along with the length of side, then we can use below mentioned formula to calculate it’s area.
Area of Equilateral Triangle = (1/2) x Side x Altitude

**Area of Equilateral triangle :**

**Perimeter of Equilateral Triangle : **

Perimeter of Equilateral Triangle : 3 X a

**How does the area formula work?**

Let us take a look at below diagram. We know are of a triangle is 1/2 * base * height. The value of h is sqrt(a^{2} – (a/2)^{2}) = sqrt(3) * a / 2. So the area becomes 1/2 * a * (sqrt(3) * a / 2) = (sqrt(3)/4) * a * a

**Examples :**

Input : side = 4 Output : Area of Equilateral Triangle: 6.9282 Perimeter of Equilateral Triangle: 12 Input : side = 12 Output : Area of Equilateral Triangle: 62.3538 Perimeter of Equilateral Triangle: 36

## C++

`// CPP program to find area ` `// and perimeter of equilateral triangle ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `// Function to calculate Area ` `// of equilateral triangle ` `float` `area_equi_triangle(` `float` `side) ` `{ ` ` ` `return` `sqrt` `(3) / 4 * side * side; ` `} ` ` ` `// Function to calculate Perimeter ` `// of equilateral triangle ` `float` `peri_equi_triangle(` `float` `side) ` `{ ` ` ` `return` `3 * side; ` `} ` ` ` `// Driver Code ` `int` `main() ` `{ ` ` ` `float` `side = 4; ` ` ` `cout << ` `"Area of Equilateral Triangle: "` ` ` `<< area_equi_triangle(side) << endl; ` ` ` `cout << ` `"Perimeter of Equilateral Triangle: "` ` ` `<< peri_equi_triangle(side); ` ` ` `return` `0; ` `} ` |

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## Java

`// Java Program to to find area and ` `// perimeter of equilateral triangle ` `import` `java.io.*; ` ` ` `class` `GFG ` `{ ` ` ` `// Function to calculate ` ` ` `// Area of equilateral triangle ` ` ` `static` `float` `area_equi_triangle(` `float` `side) ` ` ` `{ ` ` ` ` ` `return` `(` `float` `)(((Math.sqrt(` `3` `)) / ` `4` `) * ` ` ` `side * side); ` ` ` `} ` ` ` ` ` `// Function to calculate ` ` ` `// Perimeter of equilateral ` ` ` `// triangle ` ` ` `static` `float` `peri_equi_triangle(` `float` `side) ` ` ` `{ ` ` ` `return` `3` `* side; ` ` ` `} ` ` ` ` ` `// Driver Code ` ` ` `public` `static` `void` `main(String arg[]) ` ` ` `{ ` ` ` `float` `side = ` `4` `; ` ` ` `System.out.print(` `"Area of Equilateral Triangle:"` `); ` ` ` `System.out.println(area_equi_triangle(side)); ` ` ` `System.out.print(` `"Perimeter of Equilateral Triangle:"` `); ` ` ` `System.out.println(peri_equi_triangle(side)); ` ` ` `} ` `} ` ` ` `// This code is contributed ` `// by Anant Agarwal. ` |

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## Python

`# Python3 program to calculate Area and ` `# Perimeter of equilateral Triangle ` ` ` `# Importing Math library for sqrt ` `from` `math ` `import` `*` ` ` `# Function to calculate Area ` `# of equilateral triangle ` `def` `area_equilateral( side ): ` ` ` `area ` `=` `(sqrt(` `3` `) ` `/` `4` `) ` `*` `side ` `*` `side ` ` ` `print` `(` `"Area of Equilateral Triangle: % f"` `%` `area) ` ` ` `# Function to calculate Perimeter ` `# of equilateral triangle ` `def` `perimeter( side ): ` ` ` `perimeter ` `=` `3` `*` `side ` ` ` `print` `(` `"Perimeter of Equilateral Triangle: % f"` `%` `perimeter) ` ` ` `# Driver code ` `side ` `=` `4` `area_equilateral( side ) ` `perimeter( side ) ` |

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## C#

`// C# Program to to find area and ` `// perimeter of equilateral triangle ` `using` `System; ` ` ` `class` `GFG ` `{ ` ` ` `// Function to calculate ` ` ` `// Area of equilateral triangle ` ` ` `static` `float` `area_equi_triangle(` `float` `side) ` ` ` `{ ` ` ` ` ` `return` `(` `float` `)(((Math.Sqrt(3)) / 4) * ` ` ` `side * side); ` ` ` `} ` ` ` ` ` `// Function to calculate ` ` ` `// Perimeter of equilateral ` ` ` `// triangle ` ` ` `static` `float` `peri_equi_triangle(` `float` `side) ` ` ` `{ ` ` ` `return` `3 * side; ` ` ` `} ` ` ` ` ` `// Driver Code ` ` ` `public` `static` `void` `Main() ` ` ` `{ ` ` ` `float` `side = 4; ` ` ` `Console.Write(` `"Area of Equilateral Triangle:"` `); ` ` ` `Console.WriteLine(area_equi_triangle(side)); ` ` ` `Console.Write(` `"Perimeter of Equilateral Triangle:"` `); ` ` ` `Console.WriteLine(peri_equi_triangle(side)); ` ` ` `} ` `} ` ` ` `// This code is contributed ` `// by vt_m. ` |

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## PHP

`<?php ` `// PHP program to find area ` `// and perimeter of equilateral triangle ` ` ` ` ` `// Function to calculate Area ` `// of equilateral triangle ` `function` `area_equi_triangle( ` `$side` `) ` `{ ` ` ` `return` `sqrt(3) / 4 * ` `$side` `* ` `$side` `; ` `} ` ` ` `// Function to calculate Perimeter ` `// of equilateral triangle ` `function` `peri_equi_triangle( ` `$side` `) ` `{ ` ` ` `return` `3 * ` `$side` `; ` `} ` ` ` `// Driver Code ` ` ` `$side` `= 4; ` `echo` `(` `"Area of Equilateral Triangle: "` `); ` `echo` `(area_equi_triangle(` `$side` `)); ` `echo` `(` `"\n"` `); ` `echo` `(` `"Perimeter of Equilateral Triangle: "` `); ` `echo` `( peri_equi_triangle(` `$side` `)); ` ` ` `// This code is contributed ` `// by vt_m. ` `?> ` |

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**Output :**

Area of Equilateral Triangle: 6.9282 Perimeter of Equilateral Triangle: 12

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