Finding the Fourth Proportional to 56,415.72, 77,854.55 and 30,921.89

Step by Step Solution

1. Step 1: Write the proportion equation
   56,415.72 : 77,854.55 = 30,921.89 : x
2. Step 2: Convert to fraction form
   56,415.72/77,854.55 = 30,921.89/x
3. Step 3: Cross multiply
   56,415.72x = 77,854.55 × 30,921.89
4. Step 4: Simplify right side
   56,415.72x = 2,407,409,287.22
5. Step 5: Solve for x
   x = 2,407,409,287.22/56,415.72
6. Step 6: Final answer
   x = 42,672.67