Finding the Fourth Proportional to 5,128.92, 7,077.78 and 2,890.76

Step by Step Solution

1. Step 1: Write the proportion equation
   5,128.92 : 7,077.78 = 2,890.76 : x
2. Step 2: Convert to fraction form
   5,128.92/7,077.78 = 2,890.76/x
3. Step 3: Cross multiply
   5,128.92x = 7,077.78 × 2,890.76
4. Step 4: Simplify right side
   5,128.92x = 20,460,127.92
5. Step 5: Solve for x
   x = 20,460,127.92/5,128.92
6. Step 6: Final answer
   x = 3,989.17