Finding the Fourth Proportional to 1,389.80, 1,918.01 and 760.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.80 : 1,918.01 = 760.31 : x
2. Step 2: Convert to fraction form
   1,389.80/1,918.01 = 760.31/x
3. Step 3: Cross multiply
   1,389.80x = 1,918.01 × 760.31
4. Step 4: Simplify right side
   1,389.80x = 1,458,268.79
5. Step 5: Solve for x
   x = 1,458,268.79/1,389.80
6. Step 6: Final answer
   x = 1,049.26