4.14.6

Fractions of Circles

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Fractions of Circles

Arc length

Arc length

  • An arc length is a fraction of the circumference of the circle:
    • Arc length = angle360 × circumference of circle
    • Arc length = angle360 × 2πr
Area of a sector

Area of a sector

  • The area of a sector is a fraction of the area of the circle:
    • Area of sector = angle360 × πr2
Area of a segment

Area of a segment

  • To find the area of a segment, find the area of the full sector and subtract the area of the triangle using the formula:
    • Area of triangle = 12 × ab × sin(C)
  • Therefore:
    • Area of segment = (angle360 × πr2) - (12 × ab × sin(C))
Jump to other topics
1

Number

1.1

Place Value & Ordering

1.2

Numerical Operations

1.3

Structure of Calculations

1.4

Fractions

1.5

Numerical Operations on Fractions

1.6

Roots & Powers

1.7

Numerical Skills

1.8

Factors & Multiples

1.9

Surds

1.10

Standard Form

1.11

Fractions, Decimals & Percentages

1.12

Percentage Change

1.13

Rounding & Estimation

1.14

Bounds & Accuracy

1.15

Using Numbers

1.16

Fractions, Decimals & Percentages

1.17

Powers & Roots

1.18

Accuracy

2

Algebra

2.1

Algebraic Notation

2.2

Substitution & Simplification

2.3

Brackets

2.4

Algebraic Fractions

2.5

Rearranging

2.6

Functions

2.7

Solving Linear Equations

2.8

Inequalities

2.9

Solving Quadratic Equations

2.10

Simultaneous Equations

2.11

Iteration

2.12

Sequences

2.13

Linear Graphs

2.14

Introduction to Algebra

2.15

Manipulating Algebra

2.16

Proofs & Functions

2.17

Straight Line Graphs

2.18

Common Graphs

2.19

Transformations & Tangents

2.20

Properties of Graphs

2.21

Solving Equations

2.22

Inequalities

2.23

Sequences

3

Ratio

3.1

Unit Conversions

3.2

Compound Units

3.3

Ratio Fundamentals

3.4

Advanced Ratio and Scale

3.5

Proportion

3.6

Algebraic Proportion

3.7

Ratios in Practice

3.8

Manipulating Ratios

3.9

Percentage & Interest

3.10

Proportion

3.11

Gradient

4

Geometry

4.1

Area & Perimeter

4.2

Angles

4.3

Trigonometry

4.4

Similarity & Congruence

4.5

Circle Geometry

4.6

Circle Theorems

4.7

Pythagoras

4.8

Surface Area

4.9

Volume

4.10

Vectors

4.11

Introduction to Geometry

4.12

Triangles & Quadrilaterals

4.13

Transformations

4.14

Circle Basics

4.15

Circle Theorems

4.16

Measurements & Units

4.17

Calculating Area

4.18

Triangle Formulae

4.19

3D Shapes

4.20

Vectors

5

Probability

6

Statistics

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