+0

# Cone measurements

0
200
4
+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
+28357
+1

Given the data you supply, your calculations are correct.

Jul 23, 2019
#2
+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
+28357
+1

Yes, it is perfectly possible!

Alan  Jul 24, 2019
#4
+597
+1

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

juriemagic  Jul 24, 2019