Answer:
52 sq mm
Explanation:
you can break it into a long rectangle in the middle with dimensions of 2(6+8) or 2(14) = 28 sq mm
the triangle on the bottom has a base of (8-4) x height of 3, which gives 6 sq mm (you have to divide by 2)
the upper left rectangle is 6 x 3 = 18 sq mm
add: 28 + 6 + 18 = 52