Banking Notes / Quantitative Aptitude / Chapter 25
Chapter 25 of 26

Geometry

Lines, triangles, circles, and quadrilaterals with the key theorems most frequently tested in bank exams.

📖 ~9 min read 🏦 Banking Quantitative Aptitude

Introduction

Geometry in banking exams focuses on a handful of frequently repeated theorems rather than full syllabus depth — angle properties, triangle congruence/similarity, and basic circle theorems cover most of what's asked.

Key Theorems

TopicRule
Angle sum of a triangleSum of all three angles = 180°
Exterior angle theoremExterior angle = sum of the two opposite interior angles
Pythagoras theoremIn a right triangle: (Hypotenuse)² = (Base)² + (Height)²
Angle sum of a quadrilateralSum of all four angles = 360°
Angle in a semicircleAn angle inscribed in a semicircle is always 90°
Tangent-radius propertyA tangent to a circle is always perpendicular to the radius at the point of contact
Q. A right triangle has base 6 cm and height 8 cm. Find its hypotenuse.
Hypotenuse² = 6² + 8² = 36+64 = 100. Hypotenuse = √100 = 10 cm.
Q. In a triangle, two angles measure 55° and 65°. Find the third angle.
Sum of angles = 180°. Third angle = 180 − 55 − 65 = 60°.
⚠️ Key Insight: Memorise common Pythagorean triples (3-4-5, 6-8-10, 5-12-13, 9-12-15) — many bank exam right-triangle questions are built directly on these, letting you skip the calculation.
💡 Exam Tip: Geometry in banking rarely requires proofs — focus on recognising which single theorem applies to the given figure and applying it directly.
✅ Practice Focus: Triangle angle and Pythagoras problems · Circle theorems (semicircle angle, tangent-radius) · Quadrilateral angle-sum applications.

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