Finding the Fourth Proportional to 21,320.59, 31,971.16 and 12,558.01

Step by Step Solution

1. Step 1: Write the proportion equation
   21,320.59 : 31,971.16 = 12,558.01 : x
2. Step 2: Convert to fraction form
   21,320.59/31,971.16 = 12,558.01/x
3. Step 3: Cross multiply
   21,320.59x = 31,971.16 × 12,558.01
4. Step 4: Simplify right side
   21,320.59x = 401,493,924.35
5. Step 5: Solve for x
   x = 401,493,924.35/21,320.59
6. Step 6: Final answer
   x = 18,831.28