Finding the Fourth Proportional to 1,238.51, 1,857.83 and 545.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.51 : 1,857.83 = 545.15 : x
2. Step 2: Convert to fraction form
   1,238.51/1,857.83 = 545.15/x
3. Step 3: Cross multiply
   1,238.51x = 1,857.83 × 545.15
4. Step 4: Simplify right side
   1,238.51x = 1,012,784.01
5. Step 5: Solve for x
   x = 1,012,784.01/1,238.51
6. Step 6: Final answer
   x = 817.75