Finding the Fourth Proportional to 2,139.43, 3,206.72 and 906.07

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.43 : 3,206.72 = 906.07 : x
2. Step 2: Convert to fraction form
   2,139.43/3,206.72 = 906.07/x
3. Step 3: Cross multiply
   2,139.43x = 3,206.72 × 906.07
4. Step 4: Simplify right side
   2,139.43x = 2,905,512.79
5. Step 5: Solve for x
   x = 2,905,512.79/2,139.43
6. Step 6: Final answer
   x = 1,358.08