Finding the Fourth Proportional to 2,275.69, 3,139.34 and 1,389.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,275.69 : 3,139.34 = 1,389.96 : x
2. Step 2: Convert to fraction form
   2,275.69/3,139.34 = 1,389.96/x
3. Step 3: Cross multiply
   2,275.69x = 3,139.34 × 1,389.96
4. Step 4: Simplify right side
   2,275.69x = 4,363,541.33
5. Step 5: Solve for x
   x = 4,363,541.33/2,275.69
6. Step 6: Final answer
   x = 1,917.46