# Math Help - volume of revolution by integration

1. ## volume of revolution by integration

a drinking glass has the shape of a truncated cone. if the internal radii of the base and the top are 3cm and 4cm respectively and the depth is 10cm, find by integration its capacity. if the glass is filled with water to a depth of 5cm find the volume of water

ive done questions of just volume on integration where they give you an equation and the solid rotates about the X or Y axis but this question is different and i really need some help figuring out what the graph looks like, what the equation is and what im calculating

thankyou so much for any help given! =)

2. Originally Posted by flyinhigh123
a drinking glass has the shape of a truncated cone. if the internal radii of the base and the top are 3cm and 4cm respectively and the depth is 10cm, find by integration its capacity. if the glass is filled with water to a depth of 5cm find the volume of water

ive done questions of just volume on integration where they give you an equation and the solid rotates about the X or Y axis but this question is different and i really need some help figuring out what the graph looks like, what the equation is and what im calculating

thankyou so much for any help given! =)

An idea: join the points $(0,3)\,,\,\,(10,4)$ by a straight line and then revolve this line around the x-axis, what do you get? Well, this gives you the first question. About the second "cut" the glass (the line joining the points) at a distance of 5 from the center (0,0) and calculate the resulting volume.

Tonio

3. ahh ! i get it now ! thank you so much tonio for your helpp ! really appreciate it =))