Finding the Fourth Proportional to 1,380.15, 1,907.15 and 1,006.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.15 : 1,907.15 = 1,006.50 : x
2. Step 2: Convert to fraction form
   1,380.15/1,907.15 = 1,006.50/x
3. Step 3: Cross multiply
   1,380.15x = 1,907.15 × 1,006.50
4. Step 4: Simplify right side
   1,380.15x = 1,919,541.44
5. Step 5: Solve for x
   x = 1,919,541.44/1,380.15
6. Step 6: Final answer
   x = 1,390.82