Circumference and the Age of Trees Powerpoint

Capture student interest in circle calculations with this PowerPoint, which uses circumference to calculate diameter and known growth factors to convert this to age for different species of tree.
A Worksheet of 15 calculations is included, three copies on one A4, or it can be used directly from the smart board with the full class offering answers, the answers then appearing on the PowerPoint.
If you are lucky enough to have mature trees close to your classroom measuring and calculating their age introduces another dimension to our subject, and students appreciate the variation of routine as well as the real-world application of their learning. Alternatively you could set homework to identify the species of a local tree, measure it and calculate its age, (photographs and calculations produce an excellent classroom display).