Finding the Fourth Proportional to 1,389.61, 1,917.64 and 760.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.61 : 1,917.64 = 760.12 : x
2. Step 2: Convert to fraction form
   1,389.61/1,917.64 = 760.12/x
3. Step 3: Cross multiply
   1,389.61x = 1,917.64 × 760.12
4. Step 4: Simplify right side
   1,389.61x = 1,457,632.72
5. Step 5: Solve for x
   x = 1,457,632.72/1,389.61
6. Step 6: Final answer
   x = 1,048.95