First two years of secondary education. INDEX Introduction Aims Direct proportion. The rule of 3 - direct proportion. Inverse proportion. The rule of 3 - inverse proportion.
Ratio and Proportional division.
INTRODUCTION

This unit has been designed to introduce the concept of both direct and inverse proportional parts or quantities.

We will approach the above-mentioned concepts through a series of problems and exercises and also focus on methods which will allow us to apply these concepts to similar situations.

AIMS
• To introduce the concept of proportion and its properties.
• To introduce the concept of directly proportional quantities and find a method which can be used to solve problems involving these kinds of quantities.
• To introduce the concept of inversely proportional quantities and find a method which can be used to solve problems involving these kinds of quantities.
• To find similar relationships in different problems, and apply the methods explained earlier on in the unit to solve them.

 Fernando Arias Fernández-Pérez Spanish Ministry of Education. Year 2001 