Finding the Fourth Proportional to 1,039.30, 1,434.06 and 619.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.30 : 1,434.06 = 619.60 : x
2. Step 2: Convert to fraction form
   1,039.30/1,434.06 = 619.60/x
3. Step 3: Cross multiply
   1,039.30x = 1,434.06 × 619.60
4. Step 4: Simplify right side
   1,039.30x = 888,543.58
5. Step 5: Solve for x
   x = 888,543.58/1,039.30
6. Step 6: Final answer
   x = 854.94