Mathematics (AKU-MTH)
Topic 3 of 7Aga Khan Board

Geometry & Measurement

Properties of shapes, angles, area, volume and constructions

Angles:

  • Angles on a straight line sum to 180°
  • Angles at a point sum to 360°
  • Vertically opposite angles are equal
  • Interior angles of a triangle sum to 180°; quadrilateral to 360°

  • Parallel lines cut by a transversal create:

  • Alternate angles (Z-shape) — equal
  • Co-interior angles (C-shape) — add to 180°
  • Corresponding angles (F-shape) — equal

  • Areas and Volumes:

  • Rectangle: A = l × w
  • Triangle: A = ½ × base × height
  • Circle: A = πr², Circumference = 2πr
  • Cylinder: V = πr²h, Total SA = 2πr² + 2πrh
  • Cone: V = ⅓πr²h
  • Sphere: V = ⁴⁄₃πr³

  • Pythagoras' theorem: In a right-angled triangle, a² + b² = c² (c = hypotenuse).


    Construction skills: bisecting angles, perpendicular bisectors, constructing triangles using ruler and compass.

    Key Points to Remember

    • 1Angles in triangle = 180°; quadrilateral = 360°
    • 2Alternate and corresponding angles are equal
    • 3Circle area = πr², cylinder volume = πr²h
    • 4Pythagoras: a² + b² = c²

    Pakistan Example

    Rooftop Water Tanks in Karachi — Volume Calculations

    A standard Karachi rooftop water tank is cylindrical with radius 0.6 m and height 1.5 m. Volume = π(0.6)²(1.5) ≈ 1.696 m³ ≈ 1696 litres. Families in areas with water shortages (like parts of Lyari or SITE) calculate this to plan daily usage. Geometry is a daily survival skill.

    Test Your Knowledge!

    3 questions to check if you understood this topic.

    Start Quiz