Arc Length Algorithm (#7610)

* Create decimal_conversions.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Create arc_length.py

* Delete decimal_conversions.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Removed redundant statement, fixed line overflow

* Update arc_length.py

Changed rad to radius as not to get confused with radians

* Update arc_length.py

* Update arc_length.py

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Chris O <46587501+ChrisO345@users.noreply.github.com>