Finding the Fourth Proportional to 1,145.96, 1,720.56 and 1,086.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,145.96 : 1,720.56 = 1,086.20 : x
2. Step 2: Convert to fraction form
   1,145.96/1,720.56 = 1,086.20/x
3. Step 3: Cross multiply
   1,145.96x = 1,720.56 × 1,086.20
4. Step 4: Simplify right side
   1,145.96x = 1,868,872.27
5. Step 5: Solve for x
   x = 1,868,872.27/1,145.96
6. Step 6: Final answer
   x = 1,630.84