FST 6-1/6-2 Notes

SA for a cone:

Volume of a cone:  $V\ =\ \frac{1}{3}\pi\cdot r^2\cdot h$  

Volume of sphere:  $V=\frac{4}{3}\pi\cdot r^3$  

 $Volume\ of\ a\ cube:\ V\ =\ x^3$  

 $Surface\ area\ of\ a\ cube:\ SA=6x^2$  

Volume of a cone:  $V\ =\ \frac{1}{3}\pi\cdot r^2\cdot h$ 

Ex) Give a formula for the radius in terms of V if height = radius.  $V\ =\ \frac{1}{3}\pi\cdot r^2\cdot h=\frac{\pi r^3}{3}\ due\ to\ h\ =\ r.$  

 $Step\ 1:\ Multiply\ by\ \frac{3}{\pi}\ to\ both\ side;\ \frac{3V}{\pi}=r^3$   $Step\ 2:\ Isolate\ r\ by\ taking\ ^3\sqrt{ }\ to\ both\ sides;\ ^3\sqrt{\frac{3V}{\pi}}=r$