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avatar+597 

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!

 Jul 23, 2019
 #1
avatar+28289 
+1

Given the data you supply, your calculations are correct.

 Jul 23, 2019
 #2
avatar+597 
+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
 #3
avatar+28289 
+1

Yes, it is perfectly possible!

Alan  Jul 24, 2019
 #4
avatar+597 
+1

Thank you kindly Alan!!..Have a blessed day!

juriemagic  Jul 24, 2019

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