Finding the Fourth Proportional to 21,856.95, 30,161.72 and 12,907.33

Step by Step Solution

1. Step 1: Write the proportion equation
   21,856.95 : 30,161.72 = 12,907.33 : x
2. Step 2: Convert to fraction form
   21,856.95/30,161.72 = 12,907.33/x
3. Step 3: Cross multiply
   21,856.95x = 30,161.72 × 12,907.33
4. Step 4: Simplify right side
   21,856.95x = 389,307,230.27
5. Step 5: Solve for x
   x = 389,307,230.27/21,856.95
6. Step 6: Final answer
   x = 17,811.60