Your answer would be 900m².
We can find this by finding the area of each of the shapes that make up the surface of this prism.
First there is the bottom of the prism, which would be 11 × 24 = 264m².
Then you have the two triangles on the sides of the prism, which are both (10 × 24)/2 each, which equals 120m² for each triangle. This means that the area for both triangles is 120 × 2 = 240m².
Next we have the area of the back of the prism, which is 11 × 10 = 110m².
Finally we need to find the area of the rectangle on top of the prism, which is 11 × 26 = 286m²
This means your final answer would be the sum of all of these, which is 264 + 240 + 110 + 286 = 900m².
I hope this helps!