Finding the Fourth Proportional to 806.34, 1,111.72 and 688.08

Step by Step Solution

1. Step 1: Write the proportion equation
   806.34 : 1,111.72 = 688.08 : x
2. Step 2: Convert to fraction form
   806.34/1,111.72 = 688.08/x
3. Step 3: Cross multiply
   806.34x = 1,111.72 × 688.08
4. Step 4: Simplify right side
   806.34x = 764,952.30
5. Step 5: Solve for x
   x = 764,952.30/806.34
6. Step 6: Final answer
   x = 948.67