Finding the Fourth Proportional to 1,086.10, 1,627.35 and 931.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.10 : 1,627.35 = 931.30 : x
2. Step 2: Convert to fraction form
   1,086.10/1,627.35 = 931.30/x
3. Step 3: Cross multiply
   1,086.10x = 1,627.35 × 931.30
4. Step 4: Simplify right side
   1,086.10x = 1,515,551.06
5. Step 5: Solve for x
   x = 1,515,551.06/1,086.10
6. Step 6: Final answer
   x = 1,395.41