Finding the Fourth Proportional to 30,591.80, 42,172 and 21,623.48

Step by Step Solution

1. Step 1: Write the proportion equation
   30,591.80 : 42,172 = 21,623.48 : x
2. Step 2: Convert to fraction form
   30,591.80/42,172 = 21,623.48/x
3. Step 3: Cross multiply
   30,591.80x = 42,172 × 21,623.48
4. Step 4: Simplify right side
   30,591.80x = 911,905,398.56
5. Step 5: Solve for x
   x = 911,905,398.56/30,591.80
6. Step 6: Final answer
   x = 29,808.82