Finding the Fourth Proportional to 1,039.89, 1,560.29 and 715.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.89 : 1,560.29 = 715.79 : x
2. Step 2: Convert to fraction form
   1,039.89/1,560.29 = 715.79/x
3. Step 3: Cross multiply
   1,039.89x = 1,560.29 × 715.79
4. Step 4: Simplify right side
   1,039.89x = 1,116,828.60
5. Step 5: Solve for x
   x = 1,116,828.60/1,039.89
6. Step 6: Final answer
   x = 1,073.99