Finding the Fourth Proportional to 1,039.69, 1,434.59 and 619.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.69 : 1,434.59 = 619.89 : x
2. Step 2: Convert to fraction form
   1,039.69/1,434.59 = 619.89/x
3. Step 3: Cross multiply
   1,039.69x = 1,434.59 × 619.89
4. Step 4: Simplify right side
   1,039.69x = 889,277.72
5. Step 5: Solve for x
   x = 889,277.72/1,039.69
6. Step 6: Final answer
   x = 855.33