Finding the Fourth Proportional to 1,434.86, 1,980 and 805.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,434.86 : 1,980 = 805.30 : x
2. Step 2: Convert to fraction form
   1,434.86/1,980 = 805.30/x
3. Step 3: Cross multiply
   1,434.86x = 1,980 × 805.30
4. Step 4: Simplify right side
   1,434.86x = 1,594,484.10
5. Step 5: Solve for x
   x = 1,594,484.10/1,434.86
6. Step 6: Final answer
   x = 1,111.25