Area of Square Pyramid

The sides of the polygon forming the base of a pyramid are called its base edges and the other sides of the triangles are called lateral edges. The top end of a pyramid is called its apex.[br][br]By the height of a pyramid, we mean the perpendicular distance from its apex to its base.[br][br]What is the surface area of a square pyramid with base edges 20 centimetres and lateral edges 15 centimetres?