Finding the Fourth Proportional to 1,389.06, 1,917.81 and 1,127.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.06 : 1,917.81 = 1,127.70 : x
2. Step 2: Convert to fraction form
   1,389.06/1,917.81 = 1,127.70/x
3. Step 3: Cross multiply
   1,389.06x = 1,917.81 × 1,127.70
4. Step 4: Simplify right side
   1,389.06x = 2,162,714.34
5. Step 5: Solve for x
   x = 2,162,714.34/1,389.06
6. Step 6: Final answer
   x = 1,556.96