CBSE · Class 8 · Mathematics · Chapter 14

Area

Develop strategies for calculating and comparing the areas of polygons and composite figures.

12 lessons 50 min
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Lessons in this chapter

  1. 1Understanding Area: Rectangles, Squares, and PerimeterBuild area from unit squares, distinguish it from perimeter, and solve compound rectangle, path, strip, and scaling problems.
  2. 2Area of a TriangleDerive the triangle area formula from rectangles, understand base-height pairs, and justify the formula for acute, right, and obtuse triangles.
  3. 3Using Triangle Area to Solve ProblemsUse equal-area reasoning, alternative base-height pairs, rectangle diagonals, medians, and midpoint constructions to solve geometric problems.
  4. 4Triangles Between Parallel LinesUnderstand equal-area triangles on a common base between parallels and use reflection to solve minimum-perimeter and shortest-path problems.
  5. 5Equal-Area Transformations and Geometric DissectionUse cutting and rearrangement to transform rectangles and triangles while preserving area, with connections to classical Indian geometric constructions.
  6. 6Area of Any PolygonFind areas of quadrilaterals, pentagons, hexagons, and shaded regions by triangulating, adding, and subtracting simpler areas.
  7. 7Area of a ParallelogramDerive the parallelogram area formula by dissection, distinguish side length from height, and solve equal-area and missing-dimension problems.
  8. 8Area of a RhombusUse both base-height and diagonal methods for rhombus area, derive the diagonal formula by dissection and triangles, and solve inverse problems.
  9. 9Area of a TrapeziumDerive the trapezium area formula by decomposition, identify the correct height, interpret the formula using the average of the parallel sides, and solve applications.
  10. 10More Ways to Understand Trapezium AreaProve the trapezium formula using two copies and alternative dissections, transform trapeziums to equal-area rectangles, and solve advanced area relationships.
  11. 11Areas in Real LifeEstimate and measure everyday areas, convert between squared units correctly, and understand larger land units from square feet to square kilometres.
  12. 12Summary and PracticeConsolidate the chapter through formula reasoning, common-error checks, mixed worked examples, conceptual questions, and cumulative practice.
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