Finding the Fourth Proportional to 21,690.21, 29,932.71 and 12,740.58

Step by Step Solution

1. Step 1: Write the proportion equation
   21,690.21 : 29,932.71 = 12,740.58 : x
2. Step 2: Convert to fraction form
   21,690.21/29,932.71 = 12,740.58/x
3. Step 3: Cross multiply
   21,690.21x = 29,932.71 × 12,740.58
4. Step 4: Simplify right side
   21,690.21x = 381,360,086.37
5. Step 5: Solve for x
   x = 381,360,086.37/21,690.21
6. Step 6: Final answer
   x = 17,582.13