Finding the Fourth Proportional to 1,389.34, 1,914.60 and 1,057.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.34 : 1,914.60 = 1,057.24 : x
2. Step 2: Convert to fraction form
   1,389.34/1,914.60 = 1,057.24/x
3. Step 3: Cross multiply
   1,389.34x = 1,914.60 × 1,057.24
4. Step 4: Simplify right side
   1,389.34x = 2,024,191.70
5. Step 5: Solve for x
   x = 2,024,191.70/1,389.34
6. Step 6: Final answer
   x = 1,456.94