ii - edupub.gov.lk

1 IiFirst Print 2014 Second Print 2015 Third Print 2016 Fourth Print 2017 Fifth Print 2018 Sixth Print 2019 All Rights ReservedISBN 978-955-25-0188-3 State Printing CorporationPanaluwa, Padukkaiii ivvv Message from the Hon. Minister of Education The past two decades have been significant in the world history due to changes that took pl ace in technology. The present students face a lot of new challenges along with the rapid development of Information Technology, communication and other related fields. The manner of career opportunities are liable to change specifically in the near future.

2 In such an environment, with a new technological and intellectual society, thousands of innovative career opportunities would be created. To win those challenges, it is the responsibility of Sri Lankan Government and myself, as the Minister of Education, to empower you all. This book is a product of free education. Your aim must be to use this book properly and acquire the necessary knowledge out of it. The government in turn is able to provide free textbooks to you, as a result of the commitment and labour of your parents and elders. Since we have understood that the education is crucial in deciding the future of a country, the government has taken steps to change curriculum to suit the rapid changes of the technological world.

3 Hence, you have to dedicate yourselves to become productive citizens. I believe that the knowledge this book provides will suffice your aim. It is your duty to give a proper value to the money spent by the government on your education. Also you should understand that education determines your future. Make sure that you reach the optimum social stratum through education. I congratulate you to enjoy the benefits of free education and bloom as an honoured citizen who takes the name of Sri Lanka to the world. Akila Viraj Kariyawasam Minister of Education Being innovative, changing with right knowledge Be a light to the country as well as to the from the Hon.

4 Minister of EducationThe past two decades have been significant in the world history due to changes that took place in technology. The present students face a lot of new challenges along with the rapid development of Information Technology, communication and other related fields. The manner of career opportunities are liable to change specifically in the near future. In such an environment, with a new technological and intellectual society, thousands of innovative career opportunities would be created. To win those challenges, it is the responsibility of the Sri Lankan Government and myself, as the Minister of Education, to empower you all.

5 This book is a product of free education. Your aim must be to use this book properly and acquire the necessary knowledge out of it. The government in turn is able to provide free textbooks to you, as a result of the commitment and labour of your parents and we have understood that the education is crucial in deciding the future of a country, the government has taken steps to change curriculum to suit the rapid changes of the technological world. Hence, you have to dedicate yourselves to become productive citizens.

6 I believe that the knowledge this book provides will suffice your aim. It is your duty to give a proper value to the money spent by the government on your education. Also you should understand that education determines your future. Make sure that you reach the optimum social stratum through congratulate you to enjoy the benefits of free education and bloom as an honoured citizen who takes the name of Sri Lanka to the world. Being innovative, changing with right knowledgeBe a light to the country as well as to the and Supervision W. M. Jayantha Wickramanayaka - Commissioner General of Educational Publications Educational Publications DepartmentDirection Nirmala Piyaseeli - Commissioner of Education Publications (Development)

7 Educational Publications DepartmentCo-ordination Thanuja Maithrie Witharana - Assistant Commissioner Educational Publications DepartmentFinal Evaluation Kulathunga - Professor, Department of Mathematics, University of Kelaniya Board of EditorsDr. Romaine Jayewardene - Senior Lecturer, Department of MathematicsUniversity of ColomboDr. Mallawa Arachchi - Senior Lecturer, Department of Mathematics University of Pragnadarshana - Senior Lecturer, Faculty of Education, University of Biyanwila - Director of Education, Ministry Of Jagath Kumara - Senior Lecturer, National Institute of EducationS.

8 Rajendram - Lecturer, National Institute of EducationThanuja Maithrie Witharana - Assistant Commissioner, Educational Publications DepartmentBoard of WritersHemamali Weerakoon - Lecturer, Pasdunrata National College of Jayasena - In Service Adviser (Retired) Vitarama - In Service Adviser, Zonal Education Office, DehiowitaAjith Ranasinghe - In Service Adviser, Zonal Education Office, HomagamaAnura Weerasinghe - In Service Adviser, (Priven), Matara Lal Wijekantha - Teacher, St. Thomas College, Mt. Dharmarathna - Teacher, Sirimavo Bandaranaike Vidyalaya, Colombo Ranjani De Silva - Teacher, Dharmapala Vidyalaya, PannipitiyaN.

9 Vakeeshamoorthi - Director of Education (Retired) Pushparajan - Assistant Director, Zonal Education Office, PuttalamK. Karuneshvaran - In Service Adviser, Zonal Education Office, Colombo Language EditingDr. J. Rathnayake - Senior Lecturer, Department of Mathematics University of ColomboProof Samurdhi - Teacher, Sirimavo Bandaranaike Vidyalaya, Colombo 07 Illustrations, Cover Page and Technical Chathurani Perera - Educational Publications Thilini Sewwandi - Educational Publications Departmentviii Message of the Board of CompilersThis textbook has been compiled in accordance with the new syllabus to be implemented from 2015.

10 Textbooks are compiled for students. Therefore, we have made an attempt to compile this textbook in a simple and detailed manner making it possible for you to read and understand it on your own. We have included descriptions , activities and examples to introduce the subject concepts in an attractive manner and to establish them. Moreover, activities are organized from simple to complex to develop an interest to do them. We have used the terms related to mathematical concepts in accordance with the glossary of technical terms of mathematics compiled by the Department of Official subject matter learnt during the earlier grades is necessary to learn the subject content in the grade 10 syllabus.