Finding the Fourth Proportional to 1,005.42, 1,388.16 and 627.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.42 : 1,388.16 = 627.89 : x
2. Step 2: Convert to fraction form
   1,005.42/1,388.16 = 627.89/x
3. Step 3: Cross multiply
   1,005.42x = 1,388.16 × 627.89
4. Step 4: Simplify right side
   1,005.42x = 871,603.27
5. Step 5: Solve for x
   x = 871,603.27/1,005.42
6. Step 6: Final answer
   x = 866.90