Finding the Fourth Proportional to 30,591.76, 42,248.72 and 21,056.28

Step by Step Solution

1. Step 1: Write the proportion equation
   30,591.76 : 42,248.72 = 21,056.28 : x
2. Step 2: Convert to fraction form
   30,591.76/42,248.72 = 21,056.28/x
3. Step 3: Cross multiply
   30,591.76x = 42,248.72 × 21,056.28
4. Step 4: Simplify right side
   30,591.76x = 889,600,877.96
5. Step 5: Solve for x
   x = 889,600,877.96/30,591.76
6. Step 6: Final answer
   x = 29,079.75