Finding the Fourth Proportional to 1,401.98, 2,103.08 and 428.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.98 : 2,103.08 = 428.09 : x
2. Step 2: Convert to fraction form
   1,401.98/2,103.08 = 428.09/x
3. Step 3: Cross multiply
   1,401.98x = 2,103.08 × 428.09
4. Step 4: Simplify right side
   1,401.98x = 900,307.52
5. Step 5: Solve for x
   x = 900,307.52/1,401.98
6. Step 6: Final answer
   x = 642.17