Finding the Fourth Proportional to 1,390.01, 1,917.89 and 830.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.01 : 1,917.89 = 830.36 : x
2. Step 2: Convert to fraction form
   1,390.01/1,917.89 = 830.36/x
3. Step 3: Cross multiply
   1,390.01x = 1,917.89 × 830.36
4. Step 4: Simplify right side
   1,390.01x = 1,592,525.40
5. Step 5: Solve for x
   x = 1,592,525.40/1,390.01
6. Step 6: Final answer
   x = 1,145.70