4.9.11

Surface Area & Composite Shapes

Test yourself on Surface Area & Composite Shapes

Test your knowledge with free interactive questions on Seneca — used by over 10 million students.

Surface Area of 3D Shapes

The surface area of a 3D shape is the total area of all its surfaces. For a shape with only flat faces, calculate the area of each face individually then add them together.

Cube

Cube

  • A cube of side length 3cm has 6 faces each with area 9cm2 so the total surface area is 54cm2.
  • Drawing a net can be helpful for calculating the total area.
Sphere

Sphere

  • The surface area of a sphere is:
    • Area = 4πr2
Cylinder

Cylinder

  • The surface area of a cylinder is: Area = 2πrh + 2πr2
  • The length of the rectangular surface is the circumference of the base.
Cone

Cone

  • The surface of a cone is: Area = πrL + πr2
  • Where L is the slant height.

Composite Shapes

A composite shape is formed when we glue two or more shapes together.

Volume

Volume

  • When two solids are glued together into a composite solid, add the volumes together.
Surface area

Surface area

  • When two 3D shapes are glued together to form a composite, the glued faces should not be included in the surface area.
Surface area - example

Surface area - example

  • If we glue two cubes of side length 3cm together along one face the total surface area is:
    • 10 × 9cm2 = 90cm2
  • Since there are 12 faces total, but two are not on the outside of the object.
Jump to other topics
1

Number

1.1

Using Numbers

1.2

Fractions, Decimals & Percentages

1.3

Powers & Roots

1.4

Accuracy

2

Algebra

2.1

Introduction to Algebra

2.2

Manipulating Algebra

2.3

Proofs & Functions

2.4

Straight Line Graphs

2.5

Common Graphs

2.6

Transformations & Tangents

2.7

Properties of Graphs

2.8

Solving Equations

2.9

Inequalities

2.10

Sequences

3

Ratio

4

Geometry

4.1

Introduction to Geometry

4.2

Triangles & Quadrilaterals

4.3

Transformations

4.4

Circle Basics

4.5

Circle Theorems

4.6

Measurements & Units

4.7

Calculating Area

4.8

Triangle Formulae

4.9

3D Shapes

4.10

Vectors

5

Probability

6

Statistics

Practice questions on Surface Area & Composite Shapes

Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
Answer all questions on Surface Area & Composite Shapes

Unlock your full potential with Seneca Premium

  • Unlimited access to 10,000+ open-ended exam questions

  • Mini-mock exams based on your study history

  • Unlock 800+ premium courses & e-books

Get started with Seneca Premium