Pyramids and Cones
Part of the Surface Area & Volume section of Coddy's Geometry journey. Lesson 3 of 62.
Some solids narrow to a point. A pyramid has a flat base, and triangles rise from every edge of the base to meet at one point at the top, the apex. In this course the base is a square and the apex sits straight above its centre, which is called a right square pyramid.
The height of a pyramid is the straight drop from the apex to the middle of the base. It runs inside the solid, so it is drawn dashed, and it meets the base at a right angle. Here the base edge is 6 and the height is 4.
A cone also rises from a base to an apex, like a party hat, but its base is a circle and its side is one curved surface. It is not a pyramid: a pyramid's base is a polygon with straight sides. It is measured by the radius of its base circle, from the centre out to the rim, and by its height, from the apex straight down to that centre. That holds because every cone in this course is a right cone: its apex sits straight above the centre of its base.
Challenge
Tap the radius of the cone's base, then press Check.
Try it yourself
Find the right part on 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