# At Right Angles Issue 4 July 2019

Description:
AtRiA continues its March, July and November pattern with this, the second issue for 2019. Our cover this time is based on Jonaki Ghosh's TechSpace article on Fractals. Seen and admired from afar, and studied with a mathematician's lens, here is the greatest excitement, generating your own fractals using dynamic geometry software.

In Features, we have the second part of Shailesh Shirali's article on in the fourth of the series on Mathematical Constants. Shashidhar Jagadeeshan invites us to dwell on an illustration of the beauty of mathematics in the first of his series, we focus this time, on Pentagons. In Vignettes of Calculus, Pythagorean surprise uses very simple calculus to explain very strange results. You are certainly going to have rich takeaways from this section.

ClassRoom, this time, has a wide variety of articles. Two articles on A - one which describes the excitement when a enters dass 5 - this has accompanying pedagogical notes, and the other, A Path to a for a more mature student. Students Ananda Bhaduri and Rahil Miraj share their understanding on Circles Inscribed in Segments and Inradius-Exradius of a Pythagorean Triangle respectively. Hara Gopal studies a new kind of triplet and how these can be generated in Cure Triplets, Swati Sircar's TearOut has a ready-made worksheet which helps a student investigate the relationships between the area and perimeter of different figures and in Sense-Making, we look at patterns, counting and generalization. Shikha Takker has thrown light on to the study of errors and misconceptions, Understanding Learner's Thinking will certainly add to the mathematics teacher's insight into the working of the student's mind.

Are paper and pencil the only tools which are used to solve problems? A Ramachandran thinks not - his Middle School Problem set are Do It Yourself and need paper, cello tape, scissors and an inquisitive mind. Usha Krishnamoorthy reviews two websites on Data Handling and tops her review with how she used these in her classroom.

Remember our code given on the Contents Page. A discreet colour band at the top of each article indicates whether it is best suited for Primary (1-5), Middle School (6-8), High School (9-10) or Pre-University (11-12). Awaiting your feedback on AtRiA.editor@apu.edu.in or on AtRiUM, our FaceBook page.

Sneha Titus, Associate Editor

Features

From Regular Pentagons to the Icosahedron via the Golden Ratio - Part 1

The Constants of Mathematics - Part 4

A Counter-intuitive PYTHAGOREAN SURPRISE

Classroom

Circles Inscribed in Segments

Radii of In-circle and Ex-circles of a Right- Angled Triangle

A path to π

π Enters the 5th Class

Understanding Learners' Thinking through an Analysis of Errors

'CuRe' TRIPLETS

Joining the Dots...

Can there be SSA congruence?

How to Prove It: Contradiction and Contrapositive

Techspace

Problem Corner

DIY Problems for the MIDDLE SCHOOL

Problems for the Senior School July 2019

A Geometric Exploration

A Triangle Area Problem