Correct option is A
Given Side Length
The side of the triangle (and the common side of the square) = 4/3 cm.
Perimeter = (3 x side of square) + (2 x side of triangle)
Perimeter = (3 x 4/3) + (2 x 4/3)
Perimeter = 4 + 8/3
Perimeter = (12/3) + (8/3)
Perimeter = 20/3 cm =