Finding the Fourth Proportional to 1,401.99, 2,103.30 and 428.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,401.99 : 2,103.30 = 428.01 : x
2. Step 2: Convert to fraction form
   1,401.99/2,103.30 = 428.01/x
3. Step 3: Cross multiply
   1,401.99x = 2,103.30 × 428.01
4. Step 4: Simplify right side
   1,401.99x = 900,233.43
5. Step 5: Solve for x
   x = 900,233.43/1,401.99
6. Step 6: Final answer
   x = 642.11