Finding the Fourth Proportional to 1,039.47, 1,434.42 and 620.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.47 : 1,434.42 = 620.10 : x
2. Step 2: Convert to fraction form
   1,039.47/1,434.42 = 620.10/x
3. Step 3: Cross multiply
   1,039.47x = 1,434.42 × 620.10
4. Step 4: Simplify right side
   1,039.47x = 889,483.84
5. Step 5: Solve for x
   x = 889,483.84/1,039.47
6. Step 6: Final answer
   x = 855.71