Answer:
Surface area of the box is 3345cm^2
Explanation:
First you need to find the surface area of the sides. In order to find the sides you would do 70cm times 15cm to find one of the area of the sides. This would give you that one of the area is 1050cm^2. Since there are three you need to multiply by 3. This means that all the rectangles on the side would have a surface area of 3150cm^2. Then you need to find the area of the triangles. So the Area= Height times (1/2)base. Area= 13cm* times 7.5cm. Therefore the area of the triangle is equal to 97.5cm^2. Since there are two this means that the surface area of the two triangles would be equal to 195cm^2. Then in order to find the total surface area you would need to add the triangles with the rectangles which is equal to 3150cm^2 plus 195cm^2 which totals to 3345cm^2.
Therefore the total surface area for the triangle box is 3345cm^2