|[http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-I-Maths-EM.pdf Tamilnadu Textbook Class - IX - Chapter - 4 - Geometry] | |[http://www.textbooksonline.tn.nic.in/Books/Std09/Std09-I-Maths-EM.pdf Tamilnadu Textbook Class - IX - Chapter - 4 - Geometry] |