Finding the Fourth Proportional to 1,384.16, 1,908.24 and 990.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.16 : 1,908.24 = 990.48 : x
2. Step 2: Convert to fraction form
   1,384.16/1,908.24 = 990.48/x
3. Step 3: Cross multiply
   1,384.16x = 1,908.24 × 990.48
4. Step 4: Simplify right side
   1,384.16x = 1,890,073.56
5. Step 5: Solve for x
   x = 1,890,073.56/1,384.16
6. Step 6: Final answer
   x = 1,365.50