Finding the Fourth Proportional to 1,029.50, 1,421.90 and 780.38

Step by Step Solution

1. Step 1: Write the proportion equation
   1,029.50 : 1,421.90 = 780.38 : x
2. Step 2: Convert to fraction form
   1,029.50/1,421.90 = 780.38/x
3. Step 3: Cross multiply
   1,029.50x = 1,421.90 × 780.38
4. Step 4: Simplify right side
   1,029.50x = 1,109,627.83
5. Step 5: Solve for x
   x = 1,109,627.83/1,029.50
6. Step 6: Final answer
   x = 1,077.84