Finding the Fourth Proportional to 1,389.10, 1,913.06 and 1,358.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.10 : 1,913.06 = 1,358.86 : x
2. Step 2: Convert to fraction form
   1,389.10/1,913.06 = 1,358.86/x
3. Step 3: Cross multiply
   1,389.10x = 1,913.06 × 1,358.86
4. Step 4: Simplify right side
   1,389.10x = 2,599,580.71
5. Step 5: Solve for x
   x = 2,599,580.71/1,389.10
6. Step 6: Final answer
   x = 1,871.41