The middle is a square with side length of 12cm
Area of the square = 12 x 12 = 144 cm^2
There are 4 triangles with base of 13cm and height of 8 cm
Area of triangle = 1/2 x base x height
Area = 1/2 x 12 x 8 = 48cm^2 each
48 x 4 = 192 cm^2
Total area = 144 + 192 = 336 cm^2