Geometry & Mensuration
TNPSC - Group 1 Paper 1 — Quantitative Aptitude
2-min read·10 key concepts·10 facts
AI-Powered Analysis
16
PYQs Analyzed
2019–2025
Years Covered
Paper 1
TNPSC - Group 1
This subtopic covers geometric shapes and their measurements, crucial for TNPSC exams. Focus on area, volume, and properties of triangles, circles, and solids.
Key Concepts
Triangle Inequality
Sum of two sides must be greater than the third.
Area of Triangle
Using coordinates or base-height formula.
Cone and Cylinder Volume
Volume formulas for combined shapes.
Circle Area/Perimeter
Area = πr², circumference = 2πr.
Surface Area
Total surface area for cones, cylinders, spheres.
Mensuration Formulas
Area, volume, and perimeter calculations.
Cube Diagonal
Diagonal of a cube = a√3.
Cuboid Volume
Volume = length × breadth × height.
Equilateral Triangle
Area = (√3/4) × side².
Sphere Volume
Volume = (4/3)πr³.
Must-Know Facts
- 1Triangle inequality rule for sides.
- 2Area of circle = πr², circumference = 2πr.
- 3Volume of hemisphere = (2/3)πr³.
- 4Cube diagonal = a√3.
- 5Equilateral triangle area formula.
- 6Cuboid volume formula.
- 7Cone volume = (1/3)πr²h.
- 8Sphere volume = (4/3)πr³.
- 9Circle area increase with radius change.
- 10Cost calculations for fencing and leveling.
Exam Patterns
Questions often involve area and volume calculations.
Multiple-choice questions with numerical answers.
Combination of shapes like cone + cylinder.
Use of π = 22/7 in calculations.
Application of formulas in real-life scenarios.
Common Traps
Forgetting to check triangle inequality.
Confusing area and circumference formulas.
Miscalculating cube diagonal formula.
Mixing up sphere and hemisphere volumes.
Incorrectly applying equilateral triangle area formula.
Year Highlights
2024Questions on circle area increase and cube volume.
2022Cuboid height and equilateral triangle area.
2021Hemisphere volume and cuboid width.
2019Triangle sides, cost calculations, and cone-cylinder problems.
Practice these PYQs
Test yourself with the actual 16 questions on Geometry & Mensuration