Finding the Fourth Proportional to 13,526.05, 18,678.72 and 12,789.76

Step by Step Solution

1. Step 1: Write the proportion equation
   13,526.05 : 18,678.72 = 12,789.76 : x
2. Step 2: Convert to fraction form
   13,526.05/18,678.72 = 12,789.76/x
3. Step 3: Cross multiply
   13,526.05x = 18,678.72 × 12,789.76
4. Step 4: Simplify right side
   13,526.05x = 238,896,345.91
5. Step 5: Solve for x
   x = 238,896,345.91/13,526.05
6. Step 6: Final answer
   x = 17,661.94