Finding the Fourth Proportional to 1,039.67, 1,434.59 and 619.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.67 : 1,434.59 = 619.98 : x
2. Step 2: Convert to fraction form
   1,039.67/1,434.59 = 619.98/x
3. Step 3: Cross multiply
   1,039.67x = 1,434.59 × 619.98
4. Step 4: Simplify right side
   1,039.67x = 889,417.11
5. Step 5: Solve for x
   x = 889,417.11/1,039.67
6. Step 6: Final answer
   x = 855.48