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Important CAT Geometry Formulas Sheet 2026 PDF Download

Author : Lalita Vishwakarma

November 25, 2025

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Overview: Geometry is a scoring topic of the QA section of the CAT exam, testing spatial reasoning and logical thinking. To ace this section, you need to have a good hold on the CAT geometry formulas and theorems. Read the blog to know more about them!

  • Geometry includes triangles, circles, quadrilaterals, polygons, and coordinate geometry. 
  • All these shapes have their individual formulas and theorems, based on which questions are asked in the CAT exam 2026.

In this blog, we will guide you through the essential 20+ CAT Geometry Formulas, break down their importance, and provide expert tips to enhance your preparation.

Additionally, we’ll recommend some of the best books for CAT Geometry that can further solidify your knowledge and ensure you’re well-prepared for the exam.

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CAT Geometry Formulas 2026 for Polygons and Their Properties

Key Properties and CAT Geometry Formulas of a Polygon

1. Interior and Exterior Angles: Interior Angle + Exterior Angle = 180°

2. Diagonals: Number of diagonals in an n-sided polygon = n(n - 3) / 2

3. Exterior Angles:

  • The sum of all exterior angles of any polygon = 360°
  • Measure of each exterior angle of a regular polygon = 360° / n

4. Ratios:

  • Ratio of sides to diagonals in an n-sided polygon = 2 : (n - 3)
  • Ratio of interior angle to exterior angle in a regular polygon = (n - 2): 2

5. Interior Angles:

  • Sum of all interior angles of any polygon = (2n - 4) × 90° or (n-2) x 180°
  • Each interior angle of a regular polygon = [(2n - 4) × 90°] / n or [(n-2) x 180°] / n

6. Similarity: Two polygons are similar if:

  • Their corresponding angles are equal.
  • Their corresponding sides are proportional.

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CAT Geometry Formulas 2026 for Quadrilaterals and their Properties

1. Parallelogram

  • Opposite sides are equal in length and parallel (like train tracks that never meet).
  • The lines that cut across from corner to corner (diagonals) cut each other in half.

2. Rectangle

  • Opposite sides of the quadrilateral are equal.
  • All angles are right angles (90 degrees, like a corner of a square).
  • The diagonals are equal in length and bisect each other.

3. Square

  • All sides of the square are equal.
  • All angles are right angles (90 degrees).
  • The diagonals cut each other in half at a perfect right angle (90 degrees).

4. Rhombus

  • All sides are equal.
  • The diagonals cut each other in half at a perfect right angle (90 degrees). (Think of a diamond shape.)

5. Trapezium (or Trapezoid)

  • Only one pair of opposite sides is parallel.

6. Kite

  • Two pairs of sides next to each other are equal in length.
  • The diagonals cut each other at a perfect right angle (90 degrees).

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CAT Geometry Formulas 2026 for Circles

Here are the key CAT geometry formulas for Circles:

Concept

Formula

Area of Circle

πr²

Circumference

2πr

Arc Length

(θ/360) × 2πr

Sector Area

(θ/360) × πr

Find: Important Formulas for CAT 2026

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CAT Geometry Formulas 2026 for Quadrilaterals

The formula for different quadrilaterals includes the following 

Shape

Area Formula

Square

side²

Rectangle

length × breadth

Parallelogram

base × height

Trapezium

½ × (sum of parallel sides) × height

Rhombus

½ × d₁ × d₂

Check: Venn Diagram Practice Questions for CAT 2026

CAT Geometry Formulas 2026 for Polygons

The different formulas for polygons include:

Concept

Formula

Sum of Interior Angles

(n - 2) × 180°

Each Interior Angle (regular)

(n - 2) × 180° / n

Area of a Regular Polygon

½ × Perimeter × Apothem

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CAT Coordinate Geometry Formulas 2026

The important coordinate geometry formulas include:

Concept

Formula

Distance

√[(x₂ - x₁)² + (y₂ - y₁)²]

Midpoint

((x₁ + x₂)/2 , (y₁ + y₂)/2)

Slope

(y₂ - y₁) / (x₂ - x₁)

Section Formula

(mx₂ + nx₁)/(m+n), (my₂ + ny₁)/(m+n)

Click Here: Download CAT Arithmetic questions PDF with Solutions

CAT 2026 Geometry Angles and Properties

The geometry topic consists of types of angles, including complementary, adjacent, obtuse, and right angles.

Angle Type

Definition

Acute Angle

The angle is less than 90∘.

Right Angle

The angle is equal to 90∘.

Obtuse Angle

The angle that is greater than 90∘ but less than 180∘.

Straight Angle

The angle that is equal to 180∘.

Reflex Angle

The angle which is greater than 180∘ but less than 360∘.

Complementary Angles

Two angles, whose sum is 90∘, are complementary to each other.

Supplementary Angles

Two angles, whose sum is 180∘, are supplementary to each other.

Adjacent Angles

Adjacent angles must have a common side.

Linear Pair

One side must be common (e.g., OB), and these two angles must be supplementary (sum to 180∘).

Angle Bisector

A line segment that divides an angle equally into two parts and is equidistant from the two sides.

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Important Properties of a Triangle

Property 1: The sum of all the angles of a triangle = 180°

Property 2:The sum of the lengths of the two sides > the length of the third side

Property 3: The difference between any two sides of any triangle < length of the third side

Property 4:The area of any triangle can be found by using this formula:

Area of any triangle = 1/2 × base × perpendicular to base from the opposite vertex.

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Some Important Theorems of Triangles in CAT Geometry 2026

The list of important theorems of the Triangle includes:

1. Basic Proportionality Theorem (BPT)

Any line parallel to one side of a triangle divides the other two sides proportionally. So, if DE is drawn parallel to BC, then it would divide sides AB and AC proportionally.

2. Midpoint Theorem

Any line joining the midpoints of two adjacent sides of a triangle is a line segment, and then this segment is parallel to the third side.

3. Apollonius’ Theorem

In a triangle, the sum of the squares of any two sides of a triangle is equal to twice the sum of the squares of the median to the third side and the square of half the third side.

4. Interior Angle Bisector Theorem

In a triangle, the angle bisector of an angle divides the opposite side to the angle in the ratio of the remaining two sides

5. Exterior Angle Bisector Theorem

In a triangle, the angle bisector of any exterior angle of a triangle divides the side opposite to the external angle in the ratio of the remaining two sides

Check: How to prepare for Logical Reasoning for CAT? 

Use SuperGrads Free Resources 2026 Strategically

CAT VARC Mock Test 2026
CAT DILR Mock test 2026
CAT QA Mock Test 2026
CAT VARC Prep Videos 2026
CAT DILR Prep Videos 2026
CAT QA Prep Videos 2026
CAT Syllabus 2026
CAT PYQs
CAT VARC Questions

Essential Geometry Theorems for CAT 2026

Apart from the essential CAT geometry formulas, the candidates also need to learn the critical theorems. Some of the key theorems you must know:

Theorem

Explanation

Basic Proportionality Theorem (Thales)

If a line is drawn parallel to one side of a triangle, it divides the other two sides proportionally.

Angle Bisector Theorem

The angle bisector of a triangle divides the opposite side in the ratio of the adjacent sides.

Pythagoras Theorem

Applies only in right-angled triangles.

Similarity of Triangles

If two triangles have corresponding angles equal, they are similar.

Cyclic Quadrilateral

Opposite angles of a cyclic quadrilateral are supplementary.

Tangents from a Point

The tangents drawn from an external point to a circle are equal in length.

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Know more: CAT DILR Syllabus Overview

Conclusion

Geometry might seem a bit tricky at first with all the shapes, lines, and formulas. But don't worry! It's all about understanding the basic geometry formulas for CAT and theorems and practising regularly. Remember, every shape has a story, and each formula helps you solve a piece of the puzzle. 

So, take your time, learn those key CAT geometry formulas and theorems, and don't be afraid to draw diagrams. 

With a little bit of practice and confidence, you'll find that geometry can actually be one of the most interesting and score-boosting parts of the CAT exam. Grab those geometry notes, keep practising, and get ready to ace those questions!

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Frequently Asked Questions

What are the most important geometry formulas to remember for CAT?

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Are geometry questions in CAT difficult?

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How many geometry questions are asked in CAT?

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What are some tips to solve CAT geometry questions faster?

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Are coordinate geometry questions common in CAT?

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Where can I find a complete list of CAT Geometry Formulas for revision?

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Are there any shortcut techniques for applying CAT Geometry Formulas in the exam?

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About the Author

Faculty
Lalita Vishwakarma

Content Writer

Lalita Vishwakarma is a professional content writer with 3 years of experience, distinguished by her ability to transform raw ideas into polished, high-impact content. She masterfully combines creative storytelling with strategic execution, ensuring that her work not only captures attention but also drives desired outcomes.... more