# Length of a Diagonal of a Parallelogram using the length of Sides and the other Diagonal

Given two integers **A** and **B**, denoting the length of a parallelogram and an integer **D**, denoting the length of a diagonal, the task is to find the length of another diagonal of the parallelogram.

**Examples:**

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Input:A = 10, B = 30, D = 20Output:40.0

Input:A = 6, B = 8, D = 10Output:10.0

**Approach:**

The relation between sides and diagonals of a parallelogram length of diagonal is given by the equation:

Below is the implementation of the above approach:

## C++

`// C++ Program to implement` `// the above approach` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Function to calculate the length` `// of the diagonal of a parallelogram` `// using two sides and other diagonal` `float` `Length_Diagonal(` `int` `a, ` `int` `b, ` `int` `d)` `{` ` ` `float` `diagonal = ` `sqrt` `(2 * ((a * a) +` ` ` `(b * b)) - (d * d));` ` ` `return` `diagonal;` `}` `// Driver Code` `int` `main()` `{` ` ` `int` `A = 10;` ` ` `int` `B = 30;` ` ` `int` `D = 20;` ` ` `// Function Call` ` ` `float` `ans = Length_Diagonal(A, B, D);` ` ` `// Print the final answer` ` ` `printf` `(` `"%0.1f"` `, ans);` ` ` `return` `0;` `}` `// This code is contributed by Rohit_ranjan` |

## Java

`// Java Program to implement` `// the above approach` `class` `GFG{` `// Function to calculate the length` `// of the diagonal of a parallelogram` `// using two sides and other diagonal` `static` `float` `Length_Diagonal(` `int` `a, ` `int` `b, ` `int` `d)` `{` ` ` `float` `diagonal = (` `float` `) Math.sqrt(` `2` `* ((a * a) +` ` ` `(b * b)) - (d * d));` ` ` `return` `diagonal;` `}` `// Driver Code` `public` `static` `void` `main(String[] args)` `{` ` ` `int` `A = ` `10` `;` ` ` `int` `B = ` `30` `;` ` ` `int` `D = ` `20` `;` ` ` `// Function Call` ` ` `float` `ans = Length_Diagonal(A, B, D);` ` ` `// Print the final answer` ` ` `System.out.printf(` `"%.1f"` `, ans);` `}` `}` `// This code is contributed by Rajput-Ji` |

## Python

`# Python Program to implement` `# the above approach` `import` `math` `# Function to calculate the length` `# of the diagonal of a parallelogram` `# using two sides and other diagonal` `def` `Length_Diagonal(a, b, d):` ` ` `diagonal ` `=` `math.sqrt(` `2` `*` `((a` `*` `*` `2` `) \` ` ` `+` `(b` `*` `*` `2` `)) ` `-` `(d` `*` `*` `2` `))` ` ` `return` `diagonal` `# Driver Code` `A ` `=` `10` `B ` `=` `30` `D ` `=` `20` `# Function Call` `ans ` `=` `Length_Diagonal(A, B, D)` `# Print the final answer` `print` `(` `round` `(ans, ` `2` `))` |

## C#

`// C# Program to implement` `// the above approach` `using` `System;` `class` `GFG{` `// Function to calculate the length` `// of the diagonal of a parallelogram` `// using two sides and other diagonal` `static` `float` `Length_Diagonal(` `int` `a, ` `int` `b, ` `int` `d)` `{` ` ` `float` `diagonal = (` `float` `) Math.Sqrt(2 * ((a * a) +` ` ` `(b * b)) - (d * d));` ` ` `return` `diagonal;` `}` `// Driver Code` `public` `static` `void` `Main(String[] args)` `{` ` ` `int` `A = 10;` ` ` `int` `B = 30;` ` ` `int` `D = 20;` ` ` `// Function Call` ` ` `float` `ans = Length_Diagonal(A, B, D);` ` ` `// Print the readonly answer` ` ` `Console.Write(` `"{0:F1}"` `, ans);` `}` `}` `// This code is contributed by Rajput-Ji` |

## Javascript

`<script>` `// javascript Program to implement` `// the above approach` `// Function to calculate the length` `// of the diagonal of a parallelogram` `// using two sides and other diagonal` `function` `Length_Diagonal( a, b, d)` `{` ` ` `let diagonal = Math.sqrt(2 * ((a * a) +` ` ` `(b * b)) - (d * d));` ` ` `return` `diagonal;` `}` `// Driver Code` ` ` `let A = 10;` ` ` `let B = 30;` ` ` `let D = 20;` ` ` `// Function Call` ` ` `let ans = Length_Diagonal(A, B, D);` ` ` `// Print the final answer` ` ` `document.write(ans.toFixed(1));` ` ` `// This code is contributed by gauravrajput1` `</script>` |

**Output:**

40.0

**Time Complexity:** O(1)**Auxiliary Space:** O(1)