Fix calculation bug in rectangle_area function

area.py

@@ -3,7 +3,7 @@
 def rectangle_area(length, width):
  if length < 0 or width < 0:
  raise ValueError('Length and width must be positive numbers')
- return length + width
+ return length * width
 
 def circle_area(radius):
  if radius < 0:
@@ -13,4 +13,6 @@ def circle_area(radius):
 def triangle_area(base, height):
  if base < 0 or height < 0:
  raise ValueError('Base and height must be positive numbers')
- return 0.5 * base * height
+ return 0.5 * base * height
+
+def