Key facts

  • The 2026 CET Graduation syllabus places this topic under Logical Reasoning and Mathematics: area of triangles, circles, ellipses, rectangles, spheres,...
  • A rectangle of length l and breadth b has area l x b and perimeter 2(l + b), so coverage questions and boundary questions must be separated at the sta...
  • A triangle with base b and perpendicular height h has area 1/2 x b x h; Heron's formula uses s = (a + b + c)/2 when all three sides are given.
  • A circle of radius r has area pi r^2 and circumference 2 pi r; if diameter is given, divide it by 2 before substitution.
  • An ellipse with semi-major axis a and semi-minor axis b has area pi ab; if full axes are given, both must be divided by 2 first.

Key Points at a Glance

  1. 1

    The 2026 CET Graduation syllabus places this topic under Logical Reasoning and Mathematics: area of triangles, circles, ellipses, rectangles, spheres, and cylinders.

  2. 2

    A rectangle of length l and breadth b has area l x b and perimeter 2(l + b), so coverage questions and boundary questions must be separated at the start.

  3. 3

    A triangle with base b and perpendicular height h has area 1/2 x b x h; Heron's formula uses s = (a + b + c)/2 when all three sides are given.

  4. 4

    A circle of radius r has area pi r^2 and circumference 2 pi r; if diameter is given, divide it by 2 before substitution.

  5. 5

    An ellipse with semi-major axis a and semi-minor axis b has area pi ab; if full axes are given, both must be divided by 2 first.

  6. 6

    A cylinder of radius r and height h has curved surface area 2 pi rh, total surface area 2 pi r(r + h), and volume pi r^2h; wording decides which one is required.

  7. 7

    A sphere has surface area 4 pi r^2 and volume 4/3 pi r^3, so square units and cubic units identify different quantities.

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Syllabus Boundary and First Decision

The current CET Graduation Level syllabus lists this topic in Logical Reasoning and Mathematics as area of triangles, circles, ellipses, rectangles, spheres, and cylinders. That boundary matters. This lesson therefore treats the listed figures directly and keeps the focus on the current 2026 scope.

Mensuration questions first test classification, not memorisation. A question may ask for boundary length, flat coverage, outer covering, or capacity. Boundary length gives perimeter or circumference. Flat coverage gives area. Outer covering of a solid gives surface area. Capacity gives volume. The same dimensions can therefore produce different answers depending on the asked quantity: fencing a rectangular field means perimeter, grassing it means area, painting a cylindrical pillar means curved surface area, and filling a cylindrical tank means volume.

The unit at the end is a strong internal check. Length remains in cm, m, or km. Area uses square units such as sq. cm, sq. m, or sq. km. Volume uses cubic units such as cubic cm or cubic m. If metres and centimetres appear together, convert before substitution. Adding 2 m to 30 cm without conversion changes the physical value.

Keep the first decision simple: decide whether the answer measures a line, a surface, or a solid capacity, then choose the formula.

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