Answer:
( C ) 428.1 ft²
Explanation:
Alright, we know the surface area of a shape is the area the entire outside covers. So, we just need to find the areas of each side and add them together.
Let's start with the two rectangular sides. The dimensions of both of these are 10×12. The area of rectangles can be calculated by multiplying the length and width, so let's do that. Then, we will multiply this answer by two, so we have the areas of both rectangles.
10 · 12 = 120
120 · 2 = 240
The area of the two rectangular sides is 240 ft². We have 3 sides left to solve for.
Next, we will find the area of the triangular sides. Again, we will multiply the answer by two so we have the area of both. The area of the triangle can be found by multiplying
the width by the height.
4.5 · 8.9 = 40.05
Multiply this by two for the area of both sides.
40.05 · 2 = 80.1
The area of the triangle sides is 80.1 ft².
The last side is also a rectangle, with the dimensions 9×12.
9 · 12 = 108
The bottom side has an area of 108 ft².
Now, we can add the areas together.
240 + 80.1 + 108 = 428.1
The surface area of the shape is 428.1 ft². The answer is C.
I hope this helps ^^
Good luck :)