Finding the Fourth Proportional to 1,069.98, 1,478.62 and 772.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,069.98 : 1,478.62 = 772.21 : x
2. Step 2: Convert to fraction form
   1,069.98/1,478.62 = 772.21/x
3. Step 3: Cross multiply
   1,069.98x = 1,478.62 × 772.21
4. Step 4: Simplify right side
   1,069.98x = 1,141,795.30
5. Step 5: Solve for x
   x = 1,141,795.30/1,069.98
6. Step 6: Final answer
   x = 1,067.12