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

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!

Download FREE Study Material for CAT 2026 by SuperGrads

• 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.

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

Download CAT Geometry Formulas PDF 

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: 4-sided polygon; sum of interior angles = 360°.
• Parallelogram: opposite sides parallel & equal; diagonals bisect each other.
• Rectangle: all angles 90°; diagonals are equal and bisect each other.
• Square: all sides equal and all angles 90°; diagonals are equal, perpendicular, and bisect angles.
• Rhombus: all sides equal; diagonals are perpendicular bisectors (but not necessarily equal).
• Trapezium/Trapezoid: one pair of opposite sides parallel.
• Kite: two pairs of adjacent equal sides; diagonals are perpendicular and one diagonal bisects the other.

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 CAT geometry formulas for 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

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

Use SuperGrads Free Resources 2026 Strategically

CAT VARC Mock Test 2026	Attempt a Free Mock test
CAT DILR Mock test 2026	Attempt a Free Mock test
CAT QA Mock Test 2026	Attempt a Free Mock test
CAT VARC Prep Videos 2026	Watch Now
CAT DILR Prep Videos 2026	Watch Now
CAT QA Prep Videos 2026	Watch Now
CAT Syllabus 2026	Download Now
CAT PYQs	Download Now
CAT VARC Questions	Download Now

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.

Know more: CAT DILR Syllabus Overview

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

If you want Geometry marks to feel predictable, follow a tight revision loop: formulas → 20 questions → analyse mistakes → repeat.

7-Day Geometry Revision Plan (CAT 2026)

1. Day 1: Triangles (formula sheet + similarity + area ratio) + 20 questions
2. Day 2: Circles (angles in circle, tangent-chord, sector/arc) + 20 questions
3. Day 3: Quadrilaterals (properties + areas) + 20 questions
4. Day 4: Polygons (angles/diagonals/regular polygon shortcuts) + 15–20 questions
5. Day 5: Coordinate geometry basics (distance, slope, section, lines) + 20 questions
6. Day 6: Mixed Geometry set (40 questions) + error-log update
7. Day 7: Mock-level Geometry practice + revise only the mistakes

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 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!

Read more: Practise Number System CAT Questions