Finding the Fourth Proportional to 1,339.59, 2,009.23 and 415.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.59 : 2,009.23 = 415.15 : x
2. Step 2: Convert to fraction form
   1,339.59/2,009.23 = 415.15/x
3. Step 3: Cross multiply
   1,339.59x = 2,009.23 × 415.15
4. Step 4: Simplify right side
   1,339.59x = 834,131.83
5. Step 5: Solve for x
   x = 834,131.83/1,339.59
6. Step 6: Final answer
   x = 622.68