Finding the Fourth Proportional to 1,272.65, 1,907.57 and 542.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,272.65 : 1,907.57 = 542.72 : x
2. Step 2: Convert to fraction form
   1,272.65/1,907.57 = 542.72/x
3. Step 3: Cross multiply
   1,272.65x = 1,907.57 × 542.72
4. Step 4: Simplify right side
   1,272.65x = 1,035,282.52
5. Step 5: Solve for x
   x = 1,035,282.52/1,272.65
6. Step 6: Final answer
   x = 813.49