Calculate the diameter of a circle with area 80cm^2 to two significant figures.

First you need to remember the equation area of a circle = πr2 with r being the radius. Therefore as we are given the area of the cicle we need to rearrange the equation to give us the radius. Therefore this gives us √(A/π) = r. Putting the numbers in using your calculator it gives us ≈ 5.046. However we need the diameter so this value needs to be multiplied by 2. Which gives us ≈ 10.09, but the question asks for only two significant figures therefore the correct aswer is 10.

Answered by Matthew S. Maths tutor

3302 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

3y^2 + 10y + 3


How do you find the length of the longest side of a right-angled triangle?


What is the 'Nth-term rule' in linear (arithmetic) sequences and how is it used?


You and your brother have your pocket money split in the ratio 2:7. If your brother receives £42, how much do you receive?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences