Finding the Fourth Proportional to 13,568.50, 18,721.29 and 7,899.76

Step by Step Solution

1. Step 1: Write the proportion equation
   13,568.50 : 18,721.29 = 7,899.76 : x
2. Step 2: Convert to fraction form
   13,568.50/18,721.29 = 7,899.76/x
3. Step 3: Cross multiply
   13,568.50x = 18,721.29 × 7,899.76
4. Step 4: Simplify right side
   13,568.50x = 147,893,697.89
5. Step 5: Solve for x
   x = 147,893,697.89/13,568.50
6. Step 6: Final answer
   x = 10,899.78