To find the surface area, we will first find the area of each rectangle
Area = l x w
where l is the length and w is the width
First rectangle
l=11 and w=5
Area 1 = 11 x 5 = 55mm²
Second rectangle
l=5+11+5=21 and w=4
Area 2 = 21 x 4 = 84 mm²
Third rectangle
l=11 and w=5
Area 4 = 11 x 5 = 55mm²
Fourth rectangle
l=11 and w=4
Area 4 = 11 x 4 = 44 mm²
Surface area = 55mm² + 84 mm² + 55mm² + 44mm² = 238 mm²