,so first split them into separate shapes (refer to pic) then calculate each one
I started with the triangle
8×6=48 and 48÷2=24 so the triangles area its 24
next the rectangle
12×8=96
and I did the triangle shape cut out of the square
4×3=12 12÷2=6 so its area is 6
and the squares area is 8×8=64
but u need to subtract 6 from 64 because that area is missing
then you get 64-6=58
then add all the areas
58+24+96 to get your answer of 178m