Finding the Fourth Proportional to 21,189.56, 31,749.78 and 10,787

Step by Step Solution

1. Step 1: Write the proportion equation
   21,189.56 : 31,749.78 = 10,787 : x
2. Step 2: Convert to fraction form
   21,189.56/31,749.78 = 10,787/x
3. Step 3: Cross multiply
   21,189.56x = 31,749.78 × 10,787
4. Step 4: Simplify right side
   21,189.56x = 342,484,876.86
5. Step 5: Solve for x
   x = 342,484,876.86/21,189.56
6. Step 6: Final answer
   x = 16,162.91