Question

Missy needs to paint the top and sides of a rectangular prism. The prism has a length of 25 mm. A width of 15 mm and a height of 9mm how much does she need to cover the top and sides?

Answer 1

To find the area that Missy needs to cover, we need to calculate the surface area of the rectangular prism. The surface area is equal to the sum of the areas of all six faces.

The area of the top and bottom faces (which are congruent) is length times width, or 25 mm x 15 mm = 375 mm².

The area of the front and back faces (also congruent) is height times width, or 9 mm x 15 mm = 135 mm².

The area of the left and right faces (also congruent) is length times height, or 25 mm x 9 mm = 225 mm².

Adding up the areas of all six faces, we get:

375 mm² (top) + 375 mm² (bottom) + 135 mm² (front) + 135 mm² (back) + 225 mm² (left) + 225 mm² (right) = 1,470 mm².

So Missy needs to cover 1,470 mm² of surface area.