Finding the Fourth Proportional to 1,247.59, 1,870.71 and 425.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,247.59 : 1,870.71 = 425.98 : x
2. Step 2: Convert to fraction form
   1,247.59/1,870.71 = 425.98/x
3. Step 3: Cross multiply
   1,247.59x = 1,870.71 × 425.98
4. Step 4: Simplify right side
   1,247.59x = 796,885.05
5. Step 5: Solve for x
   x = 796,885.05/1,247.59
6. Step 6: Final answer
   x = 638.74