How do I find an area in m^2 when I'm given lengths in cm?

its tempting when we're given a length in cm - let's use a radius for example - to simply square the number of cm. However this can lead you into traps. Take a circle with radius 5cm. We know that A=pir^2. It is therefore tempting to say that the Area is pi25, getting 78.5 cm^2. So far, this is correct. The issue comes when we say that 78.5cm^2 is therefore 0.785m^2. But if we imagine our radius 5cm circle in one m^2, this obviously isn't right. To help avoid this, change the units to m before you do any calculation. 5cm=0.05m. So we do A=pi0.05^2 = pi0.0025 = 0.00785m^2. This, now, is the correct answer.

LM
Answered by Lauren M. Physics tutor

2111 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

What is gravitational potential and how can gravitational potential energy be used to estimate the escape velocity of a planet of mass m and radius r?


How do you find the components of a vector?


Give the ideal gas equation, defining and justifying the inclusion of each variable, and state 5 assumptions made in the kinetic theory:


Sphere A (mass m), moving with speed 3v, collides with sphere B (mass 2m) which is moving in the opposite direction with speed v. The two spheres then combine, calculate the resulting velocity of the combined spheres.


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