We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website.
Please click on "Accept cookies" if you agree to the setting of cookies. Cookies that do not require consent remain unaffected by this, see
cookie policy and privacy policy.
DECLINE COOKIES

The diameter of a circle is increased so that the circumference increases by 70%. By what percent does the area increase?

Guest Nov 6, 2017

#1**+1 **

If the circumference - a linear measure - increases by 70%..it is now 1.7 times as large........the diameter and the radius which are also linear measures will also be 1.7 times as large.....so this is the scale factor

So......the new area will increase by the square of this scale factor = (1.7)^2 = 2.89 times = 189%

[ To see this....note that if it doubles....it increases by 100%....and if it triples, it increases by 200%

So.....2.89 times must lie between 100% and 200% ]

CPhill Nov 6, 2017