Finding the Fourth Proportional to 56,128.39, 77,456.80 and 30,977.89

Step by Step Solution

1. Step 1: Write the proportion equation
   56,128.39 : 77,456.80 = 30,977.89 : x
2. Step 2: Convert to fraction form
   56,128.39/77,456.80 = 30,977.89/x
3. Step 3: Cross multiply
   56,128.39x = 77,456.80 × 30,977.89
4. Step 4: Simplify right side
   56,128.39x = 2,399,448,152.71
5. Step 5: Solve for x
   x = 2,399,448,152.71/56,128.39
6. Step 6: Final answer
   x = 42,749.28