IXL - Surface area of pyramids and cones (Geometry practice) Improve your math knowledge with free questions in "Surface area of pyramids and cones" and thousands of other math skills. SURFACE AREA OF PYRAMID WORKSHEET - onlinemath4all Surface area of the pyramid = Sum of areas of all 5 faces. In the above pyramid, the base is a square with side length 5 cm and each wall is a triangle with base 5 cm and height 8 cm. Let us find the area of each face separately. Area of the base = 5 x 5 = 25 sq.