Finding the Fourth Proportional to 1,005.47, 1,387.69 and 580.02

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.47 : 1,387.69 = 580.02 : x
2. Step 2: Convert to fraction form
   1,005.47/1,387.69 = 580.02/x
3. Step 3: Cross multiply
   1,005.47x = 1,387.69 × 580.02
4. Step 4: Simplify right side
   1,005.47x = 804,887.95
5. Step 5: Solve for x
   x = 804,887.95/1,005.47
6. Step 6: Final answer
   x = 800.51