Finding the Fourth Proportional to 1,145.65, 1,580.85 and 648.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.65 : 1,580.85 = 648.31 : x
2. Step 2: Convert to fraction form
   1,145.65/1,580.85 = 648.31/x
3. Step 3: Cross multiply
   1,145.65x = 1,580.85 × 648.31
4. Step 4: Simplify right side
   1,145.65x = 1,024,880.86
5. Step 5: Solve for x
   x = 1,024,880.86/1,145.65
6. Step 6: Final answer
   x = 894.58