Class 12 Economics Chapter 4 The Theory of the Firm PDF NCERT Solutions for Class 12 Economics. Chapter 4 The Theory of the Firm. PDF Free Download. CBSE NCERT Study Material for School, Students. NCERT Solutions for Class 12 Economics Chapter 4: The Theory of the Firm PDF Free Download Chapter 1: Introduction Chapter 2: Theory of Consumer Behaviour Chapter 3: Production and Costs Chapter 4: The Theory of The Firm Chapter 5: Market Equilibrium Chapter 6: Non-Competitive Markets