Finding the Fourth Proportional to 1,870.54, 2,806.41 and 638.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,870.54 : 2,806.41 = 638.05 : x
2. Step 2: Convert to fraction form
   1,870.54/2,806.41 = 638.05/x
3. Step 3: Cross multiply
   1,870.54x = 2,806.41 × 638.05
4. Step 4: Simplify right side
   1,870.54x = 1,790,629.90
5. Step 5: Solve for x
   x = 1,790,629.90/1,870.54
6. Step 6: Final answer
   x = 957.28