Circles are everywhere. But when is a circle not a circle? When it’s a sphere, cylinder, or cone. In this geometry book for kids, author David A. Adler shows how circles have a diameter, radius, circumference, and area. And they have tangents, arcs, chords, major and minor sectors.
Using simple tools – ruler, paper plate, and tin can – Adler demonstrates each of these concepts. He shows how two diameters of a circle intersect in the center, and all of the circle’s radii are equal in length. Tangents, arcs, and chords are demonstrated, identifying the circle’s major and minor sectors. The circumference of a circle is determined by rolling a tin can and measuring the distance it rolls. Pi is calculated, using the radius and circumference of this circle, and kids then calculate the area of several circles, using pi.
Geometry is easy if explained in a method kids understand. This hands-on approach to circles and their characteristics should appeal to all kids, not just those naturally drawn to mathematics.
Reviewer: Alice Berger