LaSalle Preparatory School

Volume describes the space inside a 3-dimensional figure (solid).  It is measured in cubic units (ex  ft³).

In this module you will be working on finding the volume of cones, cylinders and spheres.  Each solid has it's own formula.  You will also be finding the volume of composite solids (shapes made up of two or more 'regular' solids).  

Formulas for volume:

rectangular prism: V = lwh

cylinder: V = r²h

cone: V = r²h

sphere:  

*remember:

l = length

w = width

h = height

r = radius (halfway across the 'circle')

To find the volume of a solid:

• determine the formula you will use
• substitute the given values 
• follow order of operations to simplify

When you have a composite solid, ask yourself the following questions:

• What shapes do you see?
• What formulas will you use?
• Will you add or subtract the volume of each piece to find the total volume?

Sometimes you will be given the volume of the solid and need to find one of the dimension on the right side of the formula.  Again, start by substituting all of the given values.  Simplify anything that you can on the right side of the equation (multiply).  Solve the resulting equation by dividing.