Fractional Side Lengths - Volume of Rectangular Prisms

Main Idea

Sometimes the sides of a prism are fractions or mixed numbers The formula to find volume is still the same V = l x w x h You multiply the three sides together to find how much space is inside

Step 1

Write the formula V = l x w x h

Step 2

Convert mixed numbers to improper fractions Multiply the whole number by the bottom number add the top number keep the bottom number the same Example 2 1/2 becomes 5/2 3 3/4 becomes 15/4

Step 3

Multiply the fractions Multiply the top numbers together then multiply the bottom numbers together If you have a whole number write it as a fraction over 1 Example 4 becomes 4/1

Step 4

Simplify your answer If your answer is an improper fraction turn it into a mixed number Divide the top by the bottom The answer to division is the whole number The remainder becomes the new top number The bottom number stays the same

Example Problem

Find the volume of a rectangular prism Length 2 1/2 ft Width 1 2/5 ft Height 2 3/5 ft Convert to improper