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  4. ›IB Diploma DP1
  5. ›Mathematics
  6. ›Geometry and trigonometry

IB Diploma DP1 / Mathematics / Curriculum

Geometry and trigonometry

Geometry and trigonometry: structured theory, worked examples, answered practice, and a mastery checklist for IB Diploma DP1.

CHAPTER PLAN

Learn, practise, and check your progress

Follow the steps in order or jump directly to the part you need.

—/5

completed

Estimated active study time

209 minutes

  1. 1. Understand

    Objectives, key ideas, and structured theory.

    Open →
  2. 2. Follow the method

    Worked examples that explain every step.

    Open →
  3. 3. Practise

    Graded tasks with hints and answer guidance.

    Open →
  4. 4. Consolidate

    Assignments from core work to challenge.

    Open →
  5. 5. Check

    A timed, marked test with solution guidance.

    Open →

Progress is stored only in this browser and does not require AI credits.

Learning objectives

  • ✓Recognise, explain, and apply “Trigonometric functions”.
  • ✓Recognise, explain, and apply “Radians”.
  • ✓Recognise, explain, and apply “Trigonometric identities”.
  • ✓Recognise, explain, and apply “Triangles”.
  • ✓Recognise, explain, and apply “Vectors introduction where applicable”.

Key ideas and checks

  • I select a theorem from the diagram's givens.
  • I justify every step of the solution.
  • Every solution or explanation for “Geometry and trigonometry” should include a method, justification, and final check.

Unit

Core theory

The essential chapter ideas in a clear sequence before practice.

01

Diagram, givens, target

Mark every given on the diagram and state the target clearly. Start from a relationship that connects exactly those quantities.

02

Property with justification

Every geometric step needs a property, theorem, or definition. A result without justification is not a complete proof.

03

Units and precision

Length, area, volume, and angle use different units. Round only at the end and keep sufficient intermediate precision.

04

Trigonometric functions

Draw and label every given before choosing a property or formula. Finish with estimation, an inverse operation, or substitution as a check.

05

Radians

Draw and label every given before choosing a property or formula. Finish with estimation, an inverse operation, or substitution as a check.

06

Trigonometric identities

Draw and label every given before choosing a property or formula. Finish with estimation, an inverse operation, or substitution as a check.

07

Triangles

Draw and label every given before choosing a property or formula. Finish with estimation, an inverse operation, or substitution as a check.

08

Vectors introduction where applicable

Draw and label every given before choosing a property or formula. Finish with estimation, an inverse operation, or substitution as a check.

Mathematics

Worked examples

Follow the method step by step and check why every step is valid.

Worked geometry example

A right triangle has perpendicular sides 9 cm and 12 cm. Find its hypotenuse and area.

  1. 1Pythagoras: c² = 9² + 12².
  2. 2c = √(225) = 15 cm.
  3. 3Area = 1/2 · 9 · 12.

Hypotenuse 15 cm, area 54 cm².

Reasoning example

Before calculating, explain the key idea from “Trigonometric functions” and which conditions must be checked.

  1. 1Define the idea in one clear sentence.
  2. 2Connect it to a representation, law, or formula.
  3. 3State a restriction, unit, or final check that makes the solution valid.

The answer should show not only which rule is used for “Trigonometric functions”, but also why it is valid here.

Geometry and trigonometry

Practice with answers

Eight graded tasks from core fluency to exam-style application. Work independently before opening a hint or answer.

Core fluency4 minutes

A 8 cm by 6 cm rectangle: find perimeter and area.

Hint

P = 2(l+w), A = lw.

Answer guide

P = 28 cm, A = 48 cm².

Core fluency5 minutes

A triangle has base 12 cm and height 3 cm. Find its area.

Hint

A = 1/2 bh.

Answer guide

A = 1/2 · 12 · 3 = 18 cm².

Application6 minutes

Two angles in a triangle are 70° and 50°. Find the third.

Hint

Triangle angles sum to 180°.

Answer guide

60°.

Application7 minutes

A right triangle has legs 6 cm and 8 cm. Find the hypotenuse.

Hint

Use a²+b²=c².

Answer guide

10 cm.

Reasoning8 minutes

A circle has radius 4 cm. Find circumference and area in terms of π.

Hint

C = 2πr, A = πr².

Answer guide

C = 8π cm, A = 16π cm².

Reasoning9 minutes

Scale 1:900. What real length in metres does 6 cm represent?

Hint

Multiply in cm, then convert to metres.

Answer guide

6 · 900 = 5400 cm = 54 m.

Exam style10 minutes

A cuboid is 5 cm × 3 cm × 8 cm. Find its volume.

Hint

V = lwh.

Answer guide

V = 120 cm³.

Exam style12 minutes

Points A(0,0) and B(8,5). Find AB.

Hint

AB = √(Δx²+Δy²).

Answer guide

AB = √89.

Common mistakes

  • Using a formula without checking its conditions.
  • Confusing linear, square, and cubic units.
  • Treating a not-to-scale diagram as a measurement.

Mastery check

  • ✓I select a theorem from the diagram's givens.
  • ✓I justify every step of the solution.
  • ✓I use correct units and a final check.

Geometry and trigonometry

Chapter homework

Six distinct assignments from core fluency to challenge, each with an estimated time, hint, and answer guide.

Core8 minutes

Homework 1: A 4 cm by 2 cm rectangle: find perimeter and area.

Hint

P = 2(l+w), A = lw.

Answer guide

P = 12 cm, A = 8 cm².

Core10 minutes

Homework 2: A triangle has base 28 cm and height 4 cm. Find its area.

Hint

A = 1/2 bh.

Answer guide

A = 1/2 · 28 · 4 = 56 cm².

Stretch12 minutes

Homework 3: Two angles in a triangle are 30° and 60°. Find the third.

Hint

Triangle angles sum to 180°.

Answer guide

90°.

Stretch15 minutes

Homework 4: A right triangle has legs 9 cm and 12 cm. Find the hypotenuse.

Hint

Use a²+b²=c².

Answer guide

15 cm.

Challenge18 minutes

Homework 5: A circle has radius 5 cm. Find circumference and area in terms of π.

Hint

C = 2πr, A = πr².

Answer guide

C = 10π cm, A = 25π cm².

Challenge20 minutes

Homework 6: Scale 1:500. What real length in metres does 2 cm represent?

Hint

Multiply in cm, then convert to metres.

Answer guide

2 · 500 = 1000 cm = 10 m.

50 minutes / 40 marks

Full chapter test

A timed, full-mark self-assessment with model-answer guidance.

Test timer

Ready to start

Time remaining: 50:00

Start the timer when ready, work without notes, show every step, and open model answers only after finishing.

1. A 9 cm by 2 cm rectangle: find perimeter and area.

2 marks
Answer guide

P = 22 cm, A = 18 cm².

2. A triangle has base 20 cm and height 4 cm. Find its area.

3 marks
Answer guide

A = 1/2 · 20 · 4 = 40 cm².

3. Two angles in a triangle are 80° and 60°. Find the third.

3 marks
Answer guide

40°.

4. A right triangle has legs 9 cm and 12 cm. Find the hypotenuse.

4 marks
Answer guide

15 cm.

5. A circle has radius 5 cm. Find circumference and area in terms of π.

4 marks
Answer guide

C = 10π cm, A = 25π cm².

6. Scale 1:300. What real length in metres does 2 cm represent?

4 marks
Answer guide

2 · 300 = 600 cm = 6 m.

7. A cuboid is 6 cm × 4 cm × 10 cm. Find its volume.

5 marks
Answer guide

V = 240 cm³.

8. Points A(0,0) and B(9,6). Find AB.

5 marks
Answer guide

AB = √117.

9. Similar shapes have length scale factor 1:3. If the small area is 5 cm², find the large area.

5 marks
Answer guide

5 · 3² = 45 cm².

10. Explain which givens and theorem are needed for a complete argument about “Vectors introduction where applicable”.

5 marks
Answer guide

Full response: a labelled diagram, givens, an applicable theorem with its conditions, and a logically derived conclusion.

Unit

Official sources and verification

Curriculum reference sources. Always confirm the teaching sequence with the school and tutor.

UK Department for Education - MathematicsOfficial national curriculum progression and attainment guidance.International Baccalaureate - DP curriculumOfficial DP subject structure and current subject briefs.

Mathematics

Start from the board specification and work topic by topic before full papers.

Back to subject

What this chapter covers

The structure follows the official textbook layout and is used to organise study.

Trigonometric functions
Radians
Trigonometric identities
Triangles
Vectors introduction where applicable

Where to focus

The areas that usually create mistakes or need extra revision.

I select a theorem from the diagram's givens.
I justify every step of the solution.
I use correct units and a final check.

Sources, daily material, and resources

Where to start: textbook, daily material, PDFs, videos, and worked examples.

Start from the official textbook or specification referenced on the subject page.
Use the notes and examples as support, not as a replacement for the official syllabus.
Check the current syllabus version before exam preparation.

Practice by subtopic

Targeted practice before full tests so coverage is clear.

A 8 cm by 6 cm rectangle: find perimeter and area.
A triangle has base 12 cm and height 3 cm. Find its area.
Two angles in a triangle are 70° and 50°. Find the third.
A right triangle has legs 6 cm and 8 cm. Find the hypotenuse.
A circle has radius 4 cm. Find circumference and area in terms of π.
Scale 1:900. What real length in metres does 6 cm represent?
A cuboid is 5 cm × 3 cm × 8 cm. Find its volume.
Points A(0,0) and B(8,5). Find AB.

Mocks and progress checks

How to measure progress in this chapter and when it enters a cumulative mock.

Start with untimed practice by subtopic.
Move to a short timed checkpoint only after completing the mastery checklist.
Record each error with the correct method and revisit it after 48 hours.

Next step

What to do after finishing the chapter and how it connects to the next unit.

Complete the practice without support.
Explain the core method aloud in under two minutes.
Continue to the next chapter or request targeted tutor support.

Note: for the official examinable syllabus of each school year, always confirm with the school, tutor, and current Ministry/IEP announcements.

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