D Dylonjames5 New member Joined Feb 14, 2019 Messages 1 Feb 14, 2019 #1 Could someone help me figure out how to solve for r? Thank you!

S Subhotosh Khan Super Moderator Staff member Joined Jun 18, 2007 Messages 18,241 Feb 14, 2019 #2 Dylonjames5 said: Could someone help me figure out how to solve for r? View attachment 11052 Thank you! Click to expand... \(\displaystyle \displaystyle{42.9 \ = \ \pi*\left[\dfrac{r^2*h}{3} - \dfrac{r^2(h \ - \ 7.72)^3}{3h^2}\right]}\) \(\displaystyle \displaystyle{42.9 \ = \ \pi*\dfrac{r^2}{3}\left[ h \ - \dfrac{(h \ - \ 7.72)^3}{h^2}\right]}\) continue.....

Dylonjames5 said: Could someone help me figure out how to solve for r? View attachment 11052 Thank you! Click to expand... \(\displaystyle \displaystyle{42.9 \ = \ \pi*\left[\dfrac{r^2*h}{3} - \dfrac{r^2(h \ - \ 7.72)^3}{3h^2}\right]}\) \(\displaystyle \displaystyle{42.9 \ = \ \pi*\dfrac{r^2}{3}\left[ h \ - \dfrac{(h \ - \ 7.72)^3}{h^2}\right]}\) continue.....

D Denis Senior Member Joined Feb 17, 2004 Messages 1,688 Feb 14, 2019 #3 Suggestion to "shorten/simplify" the job: let u = 42.9/pi and v = (h - 7.72)^3 So you now have: u = r^2(h) / 3 - r^2(v)/(3h^2) Solve for r. Substitute back in if necessary. Get my drift?

Suggestion to "shorten/simplify" the job: let u = 42.9/pi and v = (h - 7.72)^3 So you now have: u = r^2(h) / 3 - r^2(v)/(3h^2) Solve for r. Substitute back in if necessary. Get my drift?