Finding the Fourth Proportional to 1,389.40, 2,086.48 and 1,233.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.40 : 2,086.48 = 1,233.57 : x
2. Step 2: Convert to fraction form
   1,389.40/2,086.48 = 1,233.57/x
3. Step 3: Cross multiply
   1,389.40x = 2,086.48 × 1,233.57
4. Step 4: Simplify right side
   1,389.40x = 2,573,819.13
5. Step 5: Solve for x
   x = 2,573,819.13/1,389.40
6. Step 6: Final answer
   x = 1,852.47