Finding the Fourth Proportional to 1,401.88, 2,103.18 and 428.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.88 : 2,103.18 = 428.08 : x
2. Step 2: Convert to fraction form
   1,401.88/2,103.18 = 428.08/x
3. Step 3: Cross multiply
   1,401.88x = 2,103.18 × 428.08
4. Step 4: Simplify right side
   1,401.88x = 900,329.29
5. Step 5: Solve for x
   x = 900,329.29/1,401.88
6. Step 6: Final answer
   x = 642.23