Finding the Fourth Proportional to 21,780.24, 30,061.08 and 13,831.80

Step by Step Solution

1. Step 1: Write the proportion equation
   21,780.24 : 30,061.08 = 13,831.80 : x
2. Step 2: Convert to fraction form
   21,780.24/30,061.08 = 13,831.80/x
3. Step 3: Cross multiply
   21,780.24x = 30,061.08 × 13,831.80
4. Step 4: Simplify right side
   21,780.24x = 415,798,846.34
5. Step 5: Solve for x
   x = 415,798,846.34/21,780.24
6. Step 6: Final answer
   x = 19,090.65