Finding the Fourth Proportional to 2,139.86, 3,209.15 and 907.25

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.86 : 3,209.15 = 907.25 : x
2. Step 2: Convert to fraction form
   2,139.86/3,209.15 = 907.25/x
3. Step 3: Cross multiply
   2,139.86x = 3,209.15 × 907.25
4. Step 4: Simplify right side
   2,139.86x = 2,911,480.76
5. Step 5: Solve for x
   x = 2,911,480.76/2,139.86
6. Step 6: Final answer
   x = 1,360.60