Finding the Fourth Proportional to 21,462.72, 32,159 and 20,642.60

Step by Step Solution

1. Step 1: Write the proportion equation
   21,462.72 : 32,159 = 20,642.60 : x
2. Step 2: Convert to fraction form
   21,462.72/32,159 = 20,642.60/x
3. Step 3: Cross multiply
   21,462.72x = 32,159 × 20,642.60
4. Step 4: Simplify right side
   21,462.72x = 663,845,373.40
5. Step 5: Solve for x
   x = 663,845,373.40/21,462.72
6. Step 6: Final answer
   x = 30,930.16