Finding the Fourth Proportional to 1,688.69, 2,531.31 and 648.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,688.69 : 2,531.31 = 648.43 : x
2. Step 2: Convert to fraction form
   1,688.69/2,531.31 = 648.43/x
3. Step 3: Cross multiply
   1,688.69x = 2,531.31 × 648.43
4. Step 4: Simplify right side
   1,688.69x = 1,641,364.69
5. Step 5: Solve for x
   x = 1,641,364.69/1,688.69
6. Step 6: Final answer
   x = 971.98