Finding the Fourth Proportional to 1,390.15, 1,918.35 and 830.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.15 : 1,918.35 = 830.93 : x
2. Step 2: Convert to fraction form
   1,390.15/1,918.35 = 830.93/x
3. Step 3: Cross multiply
   1,390.15x = 1,918.35 × 830.93
4. Step 4: Simplify right side
   1,390.15x = 1,594,002.90
5. Step 5: Solve for x
   x = 1,594,002.90/1,390.15
6. Step 6: Final answer
   x = 1,146.64