Derive Perimeter of Rectangle

[nycmathguy]

Derive the formula P = 2(length) + 2(width).

 

[MathLover1]

Since the perimeter is equal to the sum of all the sides of the polygon. Hence, in the case of a rectangle, the perimeter (P) is;
P = sum of all its four sides
P = a + b + a + b (Opposite sides of rectangle are equal)
P = 2(a + b)
Hence, derived

 

[nycmathguy]

View attachment 3830

Since the perimeter is equal to the sum of all the sides of the polygon. Hence, in the case of a rectangle, the perimeter (P) is;
P = sum of all its four sides
P = a + b + a + b (Opposite sides of rectangle are equal)
P = 2(a + b)
Hence, derived

Thanks. Another nice picture. Easy explanation.