Finding Areas under Graphs (OCR GCSE Maths)

Revision Note

Test yourself
Daniel I

Author

Daniel I

Last updated

Finding Areas under Graphs

How do I estimate the area under a graph?

  • To find an estimate for the area:
    • Split area into vertical strips
    • Draw straight lines at top of strips
    • Find area of strips (trapeziums) using Area = ½(a + b)h
    • Add the areas

How do I know if my answer is an underestimate or an overestimate?

  • A common exam question is to ask if your estimate of the area is an underestimate or an overestimate
  • To answer this, simply look at the straight lines joining the tops of your strips
    • If the straight lines are below the curve, it is an underestimate
    • If the straight lines are above the curve, it is an overestimate
  • At GCSE, the lines will all be below or all be above the curve- though it may be difficult to tell which for some strips

Examiner Tip

  • This is particularly useful when working with Speed-Time and Distance-Time graphs if they are curves and not straight lines.

Worked example

estimate-of-area

estimate-of-area-answerEAG-REWRITTEN-Example-5-3-20-Diagram-2, downloadable IGCSE & GCSE Maths revision notesEstimating Areas & Gradients of Graphs Worked Example 5, downloadable IGCSE & GCSE Maths revision notes

You've read 0 of your 5 free revision notes this week

Sign up now. It’s free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Daniel I

Author: Daniel I

Expertise: Maths

Daniel has taught maths for over 10 years in a variety of settings, covering GCSE, IGCSE, A-level and IB. The more he taught maths, the more he appreciated its beauty. He loves breaking tricky topics down into a way they can be easily understood by students, and creating resources that help to do this.