Finding the Fourth Proportional to 1,087.36, 1,500.72 and 621.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.36 : 1,500.72 = 621.76 : x
2. Step 2: Convert to fraction form
   1,087.36/1,500.72 = 621.76/x
3. Step 3: Cross multiply
   1,087.36x = 1,500.72 × 621.76
4. Step 4: Simplify right side
   1,087.36x = 933,087.67
5. Step 5: Solve for x
   x = 933,087.67/1,087.36
6. Step 6: Final answer
   x = 858.12