Finding the Fourth Proportional to 1,142.78, 1,577.30 and 670.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,142.78 : 1,577.30 = 670.73 : x
2. Step 2: Convert to fraction form
   1,142.78/1,577.30 = 670.73/x
3. Step 3: Cross multiply
   1,142.78x = 1,577.30 × 670.73
4. Step 4: Simplify right side
   1,142.78x = 1,057,931.19
5. Step 5: Solve for x
   x = 1,057,931.19/1,142.78
6. Step 6: Final answer
   x = 925.76