Finding the Fourth Proportional to 1,145.05, 1,580.18 and 647.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.05 : 1,580.18 = 647.69 : x
2. Step 2: Convert to fraction form
   1,145.05/1,580.18 = 647.69/x
3. Step 3: Cross multiply
   1,145.05x = 1,580.18 × 647.69
4. Step 4: Simplify right side
   1,145.05x = 1,023,466.78
5. Step 5: Solve for x
   x = 1,023,466.78/1,145.05
6. Step 6: Final answer
   x = 893.82