June 11th, 2025

When students have completed geometric nomenclature in the lower elemenary grades, they are now ready to work with more abstract concepts such as area of triangles and circumference. We move from shapes with at least three sides to one with the most number of sides possible- circles. 
In between, we meet with parallelograms and quadrilaterals, and while the children have been exposed to polygons in the Casa, actual geometric work will only start much later for them; around eight grade. 
Our second Geometry book allows teachers and homeschoolers to introduce the more advanced concepts mentioned. We also look at the derivation of formulas- area of triangles and circumference. With their strong base in geometric hands-on resources, students who have experienced Montessori in their early years education can identify with the manipulation of concrete shapes in the explanation for the area of triangles. 
The derivation of the circumference formula in the book is a good data compilation exercise that allows students to form linkages between the different variables and identify patterns. 
Exploration of mathematical formulas, while not always accessible to students in the elementary level, allows students to rationalise why they have to use them in their work and recognise overarching patterns that are summarised into neat equations. 
You may purchase our Geometry Book II through our TPT shop here. You may also purchase a lesson plan for lower elementary geometry here. ​