Finding the Fourth Proportional to 1,380.38, 1,905.54 and 821.03

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.38 : 1,905.54 = 821.03 : x
2. Step 2: Convert to fraction form
   1,380.38/1,905.54 = 821.03/x
3. Step 3: Cross multiply
   1,380.38x = 1,905.54 × 821.03
4. Step 4: Simplify right side
   1,380.38x = 1,564,495.98
5. Step 5: Solve for x
   x = 1,564,495.98/1,380.38
6. Step 6: Final answer
   x = 1,133.38