Finding the Fourth Proportional to 1,384.23, 1,908.22 and 990.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.23 : 1,908.22 = 990.57 : x
2. Step 2: Convert to fraction form
   1,384.23/1,908.22 = 990.57/x
3. Step 3: Cross multiply
   1,384.23x = 1,908.22 × 990.57
4. Step 4: Simplify right side
   1,384.23x = 1,890,225.49
5. Step 5: Solve for x
   x = 1,890,225.49/1,384.23
6. Step 6: Final answer
   x = 1,365.54