CAT Geometry Formulas 2026 PDF (Topic-wise Formula Sheet)

This blog covers the important CAT Geometry Formulas 2026 you need for your preparation. You’ll find 20+ useful formulas and key theorems for topics such as triangles, circles, quadrilaterals, polygons, coordinate geometry, and important angle properties.

Along with the formula sheet, you’ll also get a simple 7-day + 1-day revision plan to help you revise everything quickly. You can also explore free CAT study resources, including mocks, videos, the syllabus, and previous year questions.

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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.

Read More: How to Prepare for Data Interpretation for CAT Exam?

Download CAT Geometry Formulas PDF 

What are the Geometry Formulas used in CAT 2026?

CAT geometry formulas cover triangles, circles, quadrilaterals, polygons, and coordinate geometry. Key formulas include:

• Triangle: angle sum = 180°, area = ½bh, Pythagoras: a² + b² = c²
• Quadrilateral: angle sum = 360°, rectangle area = lb, square area = s²
• Circle: circumference = 2πr, area = πr²
• Polygon: interior angle sum = (n−2) × 180°
• Coordinate geometry: distance = √[(x₂−x₁)² + (y₂−y₁)²]

These formulas are essential for solving CAT quantitative aptitude geometry questions efficiently.

CAT Geometry Formulas 2026 for Polygons (All Key Formulas)

This is your quick revision sheet for polygons in CAT Geometry—angles, diagonals, regular polygon results, and shortcuts.

Concept	Formula / Result
Sum of interior angles (n-gon)	(n − 2) × 180°
Each interior angle (regular n-gon)	[(n − 2) × 180°] / n
Sum of exterior angles (any polygon)	360°
Each exterior angle (regular n-gon)	360° / n
Number of diagonals (n-gon)	n(n − 3) / 2
Number of triangles from one vertex	(n − 2)
Central angle (regular n-gon)	360° / n
Perimeter (regular n-gon)	P = n × a (where a = side)
Area (regular n-gon)	Area = ½ × P × apothem
Apothem (from centre)	Perpendicular distance from centre to any side

CAT tip: If a regular polygon is involved, exterior angle = 360°/n is usually the fastest route to find n.

Download CAT Previous Year Papers with Answers

Read More: SuperGrads CAT Toppers Interview

CAT Geometry Formulas 2026 for Quadrilaterals (Properties + Area)

This section covers both quadrilateral properties and the most-used CAT geometry area formulas in one place.

Quadrilaterals: Key Properties

• Quadrilateral: A shape with four sides. The total of its interior angles is 360°.
• Parallelogram: Both pairs of opposite sides are parallel and equal. Its diagonals cut each other into two equal parts.
• Rectangle: All four angles are 90°. Its diagonals are equal and bisect each other.
• Square: All four sides are equal and each angle is 90°. Its diagonals are equal, meet at right angles, and also bisect the angles.
• Rhombus: All four sides are equal. Its diagonals meet at right angles and bisect each other, but the diagonals do not have to be equal.
• Trapezium/Trapezoid: A four-sided shape with one pair of opposite sides parallel.
• Kite: It has two pairs of equal sides next to each other. Its diagonals meet at right angles, and one diagonal cuts the other into two equal parts.

Quadrilaterals: Area Formulas

Shape	Area Formula
Rectangle	l × b
Square	a2
Parallelogram	base × height
Rhombus	½ × d1 × d2
Trapezium/Trapezoid	½ × (a + b) × h
Kite	½ × d1 × d2

CAT tip: In most geometry questions, height is the real game-changer. Always look for perpendiculars/altitudes first.

Know More | How Many Times CAT Exam is Conducted in a Year

CAT Geometry Formulas 2026 for Circles

Here are the key geometry formulas for CAT circles. Use θ in degrees (°) and r as radius.

Concept	Formula
Area of Circle	πr2
Circumference	2πr
Arc Length	(θ/360) × 2πr
Sector Area	(θ/360) × πr2

Quick note: If θ is in radians, Arc Length = rθ and Sector Area = ½r²θ.

Find: Important Formulas for CAT 2026

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

CAT Geometry Formulas 2026 for Coordinate Geometry

Read more: Practise Number System CAT Questions

Coordinate geometry questions in CAT become easy when your basics (distance, slope, section, and line equations) are on your fingertips.

Concept	Formula
Distance between two points	√[(x2−x1)2 + (y2−y1)2]
Midpoint	((x1+x2)/2, (y1+y2)/2)
Section formula (internal division, m:n)	((mx2+nx1)/(m+n), (my2+ny1)/(m+n))
Slope of a line	m = (y2−y1) / (x2−x1)
Equation of line (slope-intercept)	y = mx + c
Equation of line (point-slope)	y − y1 = m(x − x1)
Equation of line (two-point form)	(y − y1) = ((y2−y1)/(x2−x1))(x − x1)
Perpendicular slopes	m1 × m2 = −1
Area of triangle (coordinate method)	½ |x1(y2−y3) + x2(y3−y1) + x3(y1−y2)|

CAT tip: If the question is about ratios or “point divides a line segment”, jump straight to the section formula—it saves time.

Click Here: Download CAT Arithmetic questions PDF with Solutions

CAT Geometry Formulas 2026: Angles & Core Properties (Must-Know)

Most CAT Geometry questions crack open once you apply the right angle property. Here are the ones you should revise repeatedly.

• Linear pair: adjacent angles on a straight line sum to 180°.
• Vertically opposite angles: equal.
• Complementary angles: sum to 90°.
• Supplementary angles: sum to 180°.
• Parallel lines (transversal): alternate interior angles are equal; corresponding angles are equal; co-interior angles sum to 180°.
• Angle in a semicircle: 90°.
• Angle at centre vs circumference: angle at centre is 2× angle at circumference (same arc).
• Cyclic quadrilateral: opposite angles sum to 180°.
• Tangent ⟂ radius: tangent at a point on a circle is perpendicular to radius at that point.
• Tangent–chord theorem: angle between tangent and chord equals angle in the opposite segment.

CAT tip: If you see a circle + quadrilateral, check cyclic quadrilateral and tangent–chord first—these two alone solve a lot of questions.

Check: How to prepare for Logical Reasoning for CAT? 

CAT Geometry Formulas 2026 for Triangles (Quick Revision Sheet)

If you’re revising Geometry for CAT 2026, triangles are the highest-ROI topic. Keep this mini sheet for last-day revision and faster problem solving.

Concept	Formula / Result
Angle sum	A + B + C = 180°
Area (base-height)	Area = ½ × base × height
Area (two sides + included angle)	Area = ½ab sin(C)
Heron’s formula	Area = √[s(s−a)(s−b)(s−c)], where s = (a+b+c)/2
Inradius relation	Area = r × s
Circumradius relation	Area = abc / (4R)
Equilateral triangle (side a)	Area = (√3/4)a2, Height = (√3/2)a
Similarity shortcut	If sides ratio = k, then areas ratio = k2

CAT tip: When a triangle looks “messy”, try converting it into a similarity or area ratio question—CAT loves those.

Check: How to prepare for Quantitative Aptitude for CAT exam

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Essential Geometry Theorems for CAT 2026

Apart from the essential geometry formulas for CAT, 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.

Know more: CAT DILR Syllabus Overview

CAT Geometry Revision Strategy for CAT 2026 (7-Day + 1-Day Plan)

Geometry becomes much easier when you revise it regularly instead of trying to remember everything at once. A good way to prepare is to revise a topic, solve a few questions, and then spend some time checking where you went wrong.

7-Day Geometry Revision Plan for CAT 2026

First Day: Triangles: Begin your preparation with cat geometry notes, important topics of triangles also revise similarly. Try to complete 20 questions in a day.
Second Day: Circles: Check basic circle concepts, especially angles, tangents, arcs, and sectors. Solve 20 questions to see how well you can apply them.
Third Day: Quadrilaterals: Revise the key properties and area formulas of quadrilaterals, then practise with 20 questions.
Fourth Day: Polygons: Cover interior and exterior angles, diagonals, and the common shortcuts used for regular polygons. Practise around 15–20 questions.
Fifth Day: Coordinate Geometry: Revise distance, slope, section formula, and equations of lines. Then solve 20 questions based on these concepts.
Sixth Day: Mixed Practice: Put everything together and attempt about 40 mixed Geometry questions. Once you’re done, check the questions you got wrong and note down the concepts that need more attention.
Seventh Day: Final Practice: Treat this like a mini Geometry test. Attempt questions at the CAT level and, instead of revising everything again, focus on the formulas and concepts you tend to get wrong.

1-Day Last-Minute Revision (Before CAT 2026)

• Revise only these: Triangles + Circles + Coordinate (highest ROI).
• Do a mixed set of 25 questions with strict time limits.
• Re-check the formula tables for every question you got wrong.

Conclusion

Geometry can look confusing at first because there are so many shapes, angles, and formulas to remember. But once you get the basic concepts right, the questions become much easier to handle. The key is to understand the important CAT Geometry formulas and theorems and practise applying them to different types of questions.

While preparing, make it a habit to draw a rough diagram whenever you can. It often makes the question much easier to understand and helps you figure out which formula or theorem to use.

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!