Update Day_13.md

Author: darkprinx

Status/Day_13.md

@@ -25,6 +25,16 @@ print aCircle.area()
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 **My Solution: Python 3**
 ```
+class Circle():
+ def __init__(self,r):
+ self.radius = r
+
+ def area(self):
+ return 3.1416*(self.radius**2)
+
+
+circle = Circle(5)
+print(circle.area())
 ```
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