Finding the Fourth Proportional to 1,005.72, 1,387.72 and 563.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.72 : 1,387.72 = 563.56 : x
2. Step 2: Convert to fraction form
   1,005.72/1,387.72 = 563.56/x
3. Step 3: Cross multiply
   1,005.72x = 1,387.72 × 563.56
4. Step 4: Simplify right side
   1,005.72x = 782,063.48
5. Step 5: Solve for x
   x = 782,063.48/1,005.72
6. Step 6: Final answer
   x = 777.62