Finding the Fourth Proportional to 1,145.40, 1,580.70 and 648.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.40 : 1,580.70 = 648.12 : x
2. Step 2: Convert to fraction form
   1,145.40/1,580.70 = 648.12/x
3. Step 3: Cross multiply
   1,145.40x = 1,580.70 × 648.12
4. Step 4: Simplify right side
   1,145.40x = 1,024,483.28
5. Step 5: Solve for x
   x = 1,024,483.28/1,145.40
6. Step 6: Final answer
   x = 894.43