Finding the Fourth Proportional to 1,145.18, 1,580.64 and 725.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.18 : 1,580.64 = 725.78 : x
2. Step 2: Convert to fraction form
   1,145.18/1,580.64 = 725.78/x
3. Step 3: Cross multiply
   1,145.18x = 1,580.64 × 725.78
4. Step 4: Simplify right side
   1,145.18x = 1,147,196.90
5. Step 5: Solve for x
   x = 1,147,196.90/1,145.18
6. Step 6: Final answer
   x = 1,001.76