Finding the Fourth Proportional to 1,087.76, 1,500.72 and 621.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,087.76 : 1,500.72 = 621.74 : x
2. Step 2: Convert to fraction form
   1,087.76/1,500.72 = 621.74/x
3. Step 3: Cross multiply
   1,087.76x = 1,500.72 × 621.74
4. Step 4: Simplify right side
   1,087.76x = 933,057.65
5. Step 5: Solve for x
   x = 933,057.65/1,087.76
6. Step 6: Final answer
   x = 857.78