Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Economics
Lesson Topic: Cost-minimising choice of factor inputs
Learning Objective/s:
  • Describe the main cost classifications (fixed, variable, total, average, marginal, long‑run) and their relevance to input decisions.
  • Explain the isoquant‑isocost method for locating the cost‑minimising input mix.
  • Apply the tangency condition MPL/MPK = w/r to determine the optimal labour‑capital ratio in both short‑run and long‑run contexts.
  • Analyse how short‑run constraints limit input adjustment compared with long‑run flexibility.
  • Evaluate a firm’s input choice using a diagram and calculate the cost‑minimising point.
Materials Needed:
  • Projector and screen
  • Whiteboard and markers
  • Handout with isoquant‑isocost diagram and formulas
  • Calculator or spreadsheet software
  • Worksheet with practice problems on input mix
  • Graph paper or digital drawing tool for sketches
 Introduction:
Begin with a quick poll: “Which costs can a firm change today?” Connect responses to previous lessons on cost classifications. State today’s success criteria – students will be able to draw an isoquant‑isocost diagram and use the MPL/MPK = w/r rule to identify the cost‑minimising input combination.
Lesson Structure:
  1. Do‑now (5’) – Short quiz on fixed vs. variable costs.
  2. Mini‑lecture (10’) – Review cost classifications and introduce isoquant‑isocost analysis.
  3. Guided modelling (12’) – Teacher draws an isoquant and several isocost lines, demonstrates the tangency condition.
  4. Group activity (15’) – Students use the worksheet data to plot their own isoquant‑isocost diagram and locate the cost‑minimising point.
  5. Class debrief (8’) – Groups present findings; teacher checks understanding of the MPL/MPK = w/r rule.
  6. Check for understanding (5’) – Exit ticket: write the cost‑minimising condition and explain its economic meaning.
Conclusion:
Recap the key steps of isoquant‑isocost analysis and emphasise how the tangency condition links marginal products to input prices. Collect exit tickets as a retrieval check, and assign homework to complete a second diagram with different price ratios. This reinforces the ability to adjust the input mix under varying cost conditions.