Finding the Fourth Proportional to 1,400.39, 2,100.58 and 426.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,400.39 : 2,100.58 = 426.50 : x
2. Step 2: Convert to fraction form
   1,400.39/2,100.58 = 426.50/x
3. Step 3: Cross multiply
   1,400.39x = 2,100.58 × 426.50
4. Step 4: Simplify right side
   1,400.39x = 895,885.80
5. Step 5: Solve for x
   x = 895,885.80/1,400.39
6. Step 6: Final answer
   x = 639.74