Polygons have names that show the number of sides they have. A three-dimensional (3D) shape is a solid shape. 3D shapes have three dimensions - length, width and depth. Look at the shapes of the ...

The area of the base is \(5 \times 5 = 25~cm^2\). The area of each triangular face is \((5 \times 6) \div 2 = 15~cm^2\). There are four identical triangular faces, so the total surface area is ...