Finding the Fourth Proportional to 1,039.12, 1,432.55 and 830

Step by Step Solution

1. Step 1: Write the proportion equation
   1,039.12 : 1,432.55 = 830 : x
2. Step 2: Convert to fraction form
   1,039.12/1,432.55 = 830/x
3. Step 3: Cross multiply
   1,039.12x = 1,432.55 × 830
4. Step 4: Simplify right side
   1,039.12x = 1,189,016.50
5. Step 5: Solve for x
   x = 1,189,016.50/1,039.12
6. Step 6: Final answer
   x = 1,144.25