Finding the Fourth Proportional to 981.10, 1,353.31 and 685.86

Step by Step Solution

1. Step 1: Write the proportion equation
   981.10 : 1,353.31 = 685.86 : x
2. Step 2: Convert to fraction form
   981.10/1,353.31 = 685.86/x
3. Step 3: Cross multiply
   981.10x = 1,353.31 × 685.86
4. Step 4: Simplify right side
   981.10x = 928,181.20
5. Step 5: Solve for x
   x = 928,181.20/981.10
6. Step 6: Final answer
   x = 946.06