Finding the Fourth Proportional to 1,087.88, 1,627.72 and 647.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.88 : 1,627.72 = 647.50 : x
2. Step 2: Convert to fraction form
   1,087.88/1,627.72 = 647.50/x
3. Step 3: Cross multiply
   1,087.88x = 1,627.72 × 647.50
4. Step 4: Simplify right side
   1,087.88x = 1,053,948.70
5. Step 5: Solve for x
   x = 1,053,948.70/1,087.88
6. Step 6: Final answer
   x = 968.81