Finding the Fourth Proportional to 1,039.37, 1,434.33 and 619.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.37 : 1,434.33 = 619.91 : x
2. Step 2: Convert to fraction form
   1,039.37/1,434.33 = 619.91/x
3. Step 3: Cross multiply
   1,039.37x = 1,434.33 × 619.91
4. Step 4: Simplify right side
   1,039.37x = 889,155.51
5. Step 5: Solve for x
   x = 889,155.51/1,039.37
6. Step 6: Final answer
   x = 855.48