Finding the Fourth Proportional to 21,056.42, 31,607.37 and 18,731.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,056.42 : 31,607.37 = 18,731.31 : x
2. Step 2: Convert to fraction form
   21,056.42/31,607.37 = 18,731.31/x
3. Step 3: Cross multiply
   21,056.42x = 31,607.37 × 18,731.31
4. Step 4: Simplify right side
   21,056.42x = 592,047,445.75
5. Step 5: Solve for x
   x = 592,047,445.75/21,056.42
6. Step 6: Final answer
   x = 28,117.20