Finding the Fourth Proportional to 1,339.98, 2,009.72 and 415.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,339.98 : 2,009.72 = 415.42 : x
2. Step 2: Convert to fraction form
   1,339.98/2,009.72 = 415.42/x
3. Step 3: Cross multiply
   1,339.98x = 2,009.72 × 415.42
4. Step 4: Simplify right side
   1,339.98x = 834,877.88
5. Step 5: Solve for x
   x = 834,877.88/1,339.98
6. Step 6: Final answer
   x = 623.05