# circle

## π Enters the 5th Class

I write this to tell myself that it was not a dream...

This year I taught a bunch of fifth standard kids in Sahyadri School KFI (Krishnamurti Foundation India), who, like all others of their age, were high-energy kids; they were willing to explore but found it difficult to sit down in one place. I had a great relationship with them. The air in the classroom was of love, trust and wonder!

## Area covered by Two Intersecting Circles

Websites and focus interest groups are a good source for interesting problems. But it’s rarely that one gets down to solving these; more often they go into a to-do list. We hope that the solution presented here will encourage you to try more of these. Look at the steps of the process: Visualization, definition of the problem, connection to known formulas and then good old mathematical processing. Problem solved!

## An Approximation of pi by the Law of Cosines

The approximation of π is a popular pastime of students of mathematics and I have started with the familiar age-old way, of fitting a regular polygon tightly in a circle of radius r. The vertices of the n-sided polygon are joined to the centre of the circle so that the angle subtended at the centre by each segment is 360/n. If n is sufficiently large, the perimeter of the polygon approaches the circumference 2πr of the circle and this approximation improves as the number of segments increases.

## 3 4 5 strikes again

These are excellent GeoGebra exercises for students helping them to develop and practise skills of visualisation, logical sequencing, making connections and recalling theory. Read on.

## Circles and their parts

Introduction to circle and its parts and how they are interlinked - a Shikshamitra resource.

## Circle area problem

Find the solution to the circle area problem posed in the earlier issue of AtRiA.

## Circle Time

This time the Low Floor, High Ceiling series focuses on regular polygons inscribed in circles.

## Can a Circle be a Polygon?

Can a Circle be a Polygon?

Explanation:

How many sides does a circle have?

A circle could have: 1 curved side! or infinite sides (each side being very small) or no sides.