Finding the Fourth Proportional to 1,105.58, 1,670.90 and 1,086.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.58 : 1,670.90 = 1,086.45 : x
2. Step 2: Convert to fraction form
   1,105.58/1,670.90 = 1,086.45/x
3. Step 3: Cross multiply
   1,105.58x = 1,670.90 × 1,086.45
4. Step 4: Simplify right side
   1,105.58x = 1,815,337.61
5. Step 5: Solve for x
   x = 1,815,337.61/1,105.58
6. Step 6: Final answer
   x = 1,641.97