Hi good people!,

I have something strange here...well, for me that is..

A cone with base radius = 6cm, perpendicular height (PH) = 8cm. we are asked to calculate the volume of the cone. Using __\({1 \over3 } \pi r^2*PH\) __ it calculates to 301,59 \(cm^3\). The book gets 50,27 \(cm^3\). When I look at the calc in the book, I notice they did not use \(6^2\) for the radius but only 6. Surely that is an error on their part?

but what baffles me is that when I calculate the total outer area, using the slanted height (SH), which calculates to 10 cm (Having used Pythagoras), in this formula:

\(\pi r^2 + \pi rSH\), it also calculates to 301,59 \(cm^2\).

would it be possible to please show me my error?...Thank you very much!

juriemagic Jul 23, 2019

#1

#2**+1 **

Hi Alan,

so it is possible that both volume and surface area can be the same figure?...except of course for the square and cubic results?

juriemagic
Jul 24, 2019