Surface of a Hemisphere
Part of the Surface Area & Volume section of Coddy's Geometry journey. Lesson 49 of 62.
A solid hemisphere has two parts to its outside: the curved bowl, which is half a sphere's surface, and the flat circle where it was cut.
This hemisphere has radius 4. The bowl is half of 4×pi × 4^2, so 2×pi × 16 = 32×pi. The flat circle is pi × 4^2 = 16×pi. Together they make 48π.
The rule is Surface area of a hemisphere: SA = 3×pi×r^2, two circles' worth of bowl plus one circle of lid. Forgetting the flat circle is the usual slip.
Challenge
Find the exact surface area of the solid hemisphere, flat face included, 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: Pyramids7Surface Area of Prisms
Nets and Surface AreaVolume or Surface Area?A Missing Edge AgainTriangular PrismsThe Hidden Side FirstRecap: Prism Surfaces10Spheres Outside
Surface of a SphereSurface of a HemisphereRadius From the SurfaceSurface to VolumeRecap: Spheres Outside2Volume 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