Finding the Fourth Proportional to 21,881.19, 30,196.43 and 12,928.67

Step by Step Solution

1. Step 1: Write the proportion equation
   21,881.19 : 30,196.43 = 12,928.67 : x
2. Step 2: Convert to fraction form
   21,881.19/30,196.43 = 12,928.67/x
3. Step 3: Cross multiply
   21,881.19x = 30,196.43 × 12,928.67
4. Step 4: Simplify right side
   21,881.19x = 390,399,614.00
5. Step 5: Solve for x
   x = 390,399,614.00/21,881.19
6. Step 6: Final answer
   x = 17,841.79