Surface of a Pyramid
Part of the Surface Area & Volume section of Coddy's Geometry journey. Lesson 43 of 62.
A right square pyramid's net is a square with a triangle on each side, like a star. Each triangle has the base edge for its base, and its height is the slant height, the line down the middle of the face.
This pyramid has base edge 6 and slant height 5. The base is 6^2 = 36. Each triangle is 1/2 × 6 × 5 = 15, and four of them make 60. The surface area is 36 + 60 = 96.
The rule is Surface area of a pyramid: SA = b^2 + 2×b×s, the base plus four half rectangles. Here the slant height is the one to use, not the height: the faces lean, and their own height is the slant.
Challenge
Find the surface area of the square pyramid: tap the solid, pick the rule, then press Check.
Try it yourself
Find the marked part of the figure
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Surface Area & Volume
1Solids and Their Parts
Faces, Edges and VerticesPrisms and CylindersPyramids and ConesHeight or Slant Height?Spheres and HemispheresRecap: Parts of Solids4Pyramids
Volume of a PyramidThe Slant HeightHeight From the SlantHeight From the VolumeRecap: Pyramids2Volume of Prisms
Volume of a CuboidVolume of a PrismAny Triangle EndA Missing EdgeRecap: Prism Volume3Cylinders
Volume of a CylinderHeight From the VolumeRadius From the VolumeEnough to Find It?Recap: Cylinders6Spheres and Hemispheres
Volume of a SphereHalf a SphereRadius From the VolumeSphere in a CylinderRecap: Spheres9Pyramids and Cones Outside
Surface of a PyramidSlant Height FirstSurface of a ConeThe Cone: Slant FirstRecap: Pyramid Surfaces