Adding Pythagoras Theorem

[cwh0430]

To calculate the hypothenuse, adjacent and base of the triangle

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Describe your change:

• [✓ ] Add an algorithm?
• [ ] Fix a bug or typo in an existing algorithm?
• [ ] Documentation change?

Checklist:

• [✓ ] I have read CONTRIBUTING.md.
• [✓ ] This pull request is all my own work -- I have not plagiarized.
• [✓ ] I know that pull requests will not be merged if they fail the automated tests.
• [✓ ] This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• [✓ ] All new JavaScript files are placed inside an existing directory.
• [ ✓] All filenames should use the UpperCamelCase (PascalCase) style. There should be no spaces in filenames. Example:UserProfile.js is allowed but userprofile.js,Userprofile.js,user-Profile.js,userProfile.js are not
• [✓ ] All new algorithms have a URL in its comments that points to Wikipedia or other similar explanation.
• [✓ ] If this pull request resolves one or more open issues then the commit message contains Fixes: #{$ISSUE_NO}.