The question is find the total surface area of this shape. I'm unsure if my answer is right. I take the rectangular block 12m by 24m as Area1. I take the top rectangular block 15m by 24m as Area2. I take the bottom rectangular block 20m by 24m as Area3. I take the slant rectangular block 13m by 24m as Area4. Area5&Area6 should be the same
Area1,
(12 * 24 ) = 288 m^2
Area2,
(15 * 24 ) = 360 m^2
Area3,
(20 * 24 ) = 480 m^2
Area4,
(13 * 24 ) = 312 m^2
Area5 & Area6,
2((0.5*35*12) - 12.25*pi) = 343 m^2
TOtal Surface Area = 1783.03 m^2
Am I right?
You missed a surface. In areas 5 and 6, you correctly subtracted the disks at each end of the drilled out cylinder. You did not include the the third part of the surface of the cylinder, which makes a positive contribution to the surface area.
Your area is too small by the circumference of the bore times the depth of the bore, $$ (2\pi \cdot 3.5 \,\text{m}) \cdot 24 \,\text{m} \text{.} $$