Finding the Fourth Proportional to 2,619.34, 3,929.57 and 770.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,619.34 : 3,929.57 = 770.30 : x
2. Step 2: Convert to fraction form
   2,619.34/3,929.57 = 770.30/x
3. Step 3: Cross multiply
   2,619.34x = 3,929.57 × 770.30
4. Step 4: Simplify right side
   2,619.34x = 3,026,955.77
5. Step 5: Solve for x
   x = 3,026,955.77/2,619.34
6. Step 6: Final answer
   x = 1,155.62