Finding the Fourth Proportional to 1,005.63, 1,387.76 and 656.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.63 : 1,387.76 = 656.31 : x
2. Step 2: Convert to fraction form
   1,005.63/1,387.76 = 656.31/x
3. Step 3: Cross multiply
   1,005.63x = 1,387.76 × 656.31
4. Step 4: Simplify right side
   1,005.63x = 910,800.77
5. Step 5: Solve for x
   x = 910,800.77/1,005.63
6. Step 6: Final answer
   x = 905.70