diff --git a/coordinate_conversion.cpp b/coordinate_conversion.cpp
index 06c5663..bbb99a4 100644
--- a/coordinate_conversion.cpp
+++ b/coordinate_conversion.cpp
@@ -11,7 +11,7 @@ void polar_to_cartesian(double radius, double angle, double *xCoordinate,
 void cartesian_to_polar(double xCoordinate, double yCoordinate, double *radius,
 						double *angle) {
 	*radius = std::sqrt(std::pow(xCoordinate, 2) + std::pow(yCoordinate, 2));
-	*angle = std::atan(xCoordinate);
+	*angle = std::atan(xCoordinate / yCoordinate);
 }
 
 #endif // COORDINATE_CONVERSION_H