Finding the Fourth Proportional to 1,386.40, 1,913.46 and 1,054.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,386.40 : 1,913.46 = 1,054.30 : x
2. Step 2: Convert to fraction form
   1,386.40/1,913.46 = 1,054.30/x
3. Step 3: Cross multiply
   1,386.40x = 1,913.46 × 1,054.30
4. Step 4: Simplify right side
   1,386.40x = 2,017,360.88
5. Step 5: Solve for x
   x = 2,017,360.88/1,386.40
6. Step 6: Final answer
   x = 1,455.11