Finding the Fourth Proportional to 1,390.71, 1,914.80 and 1,058.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.71 : 1,914.80 = 1,058.07 : x
2. Step 2: Convert to fraction form
   1,390.71/1,914.80 = 1,058.07/x
3. Step 3: Cross multiply
   1,390.71x = 1,914.80 × 1,058.07
4. Step 4: Simplify right side
   1,390.71x = 2,025,987.15
5. Step 5: Solve for x
   x = 2,025,987.15/1,390.71
6. Step 6: Final answer
   x = 1,456.80