Finding the Fourth Proportional to 1,270.17, 1,906.05 and 620.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,270.17 : 1,906.05 = 620.55 : x
2. Step 2: Convert to fraction form
   1,270.17/1,906.05 = 620.55/x
3. Step 3: Cross multiply
   1,270.17x = 1,906.05 × 620.55
4. Step 4: Simplify right side
   1,270.17x = 1,182,799.33
5. Step 5: Solve for x
   x = 1,182,799.33/1,270.17
6. Step 6: Final answer
   x = 931.21