Finding the Fourth Proportional to 1,087.98, 1,501.52 and 645.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.98 : 1,501.52 = 645.92 : x
2. Step 2: Convert to fraction form
   1,087.98/1,501.52 = 645.92/x
3. Step 3: Cross multiply
   1,087.98x = 1,501.52 × 645.92
4. Step 4: Simplify right side
   1,087.98x = 969,867.17
5. Step 5: Solve for x
   x = 969,867.17/1,087.98
6. Step 6: Final answer
   x = 891.44