Finding the Fourth Proportional to 1,384.20, 1,906.07 and 990.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.20 : 1,906.07 = 990.54 : x
2. Step 2: Convert to fraction form
   1,384.20/1,906.07 = 990.54/x
3. Step 3: Cross multiply
   1,384.20x = 1,906.07 × 990.54
4. Step 4: Simplify right side
   1,384.20x = 1,888,033.63
5. Step 5: Solve for x
   x = 1,888,033.63/1,384.20
6. Step 6: Final answer
   x = 1,363.99