Finding the Fourth Proportional to 13,528.21, 18,671.31 and 7,864.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,528.21 : 18,671.31 = 7,864.72 : x
2. Step 2: Convert to fraction form
   13,528.21/18,671.31 = 7,864.72/x
3. Step 3: Cross multiply
   13,528.21x = 18,671.31 × 7,864.72
4. Step 4: Simplify right side
   13,528.21x = 146,844,625.18
5. Step 5: Solve for x
   x = 146,844,625.18/13,528.21
6. Step 6: Final answer
   x = 10,854.70