Finding the Fourth Proportional to 1,018.87, 1,525.33 and 921.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,018.87 : 1,525.33 = 921.60 : x
2. Step 2: Convert to fraction form
   1,018.87/1,525.33 = 921.60/x
3. Step 3: Cross multiply
   1,018.87x = 1,525.33 × 921.60
4. Step 4: Simplify right side
   1,018.87x = 1,405,731.89
5. Step 5: Solve for x
   x = 1,405,731.89/1,018.87
6. Step 6: Final answer
   x = 1,379.70