Finding the Fourth Proportional to 13,128, 19,697.76 and 7,656

Step by Step Solution

1. Step 1: Write the proportion equation
   13,128 : 19,697.76 = 7,656 : x
2. Step 2: Convert to fraction form
   13,128/19,697.76 = 7,656/x
3. Step 3: Cross multiply
   13,128x = 19,697.76 × 7,656
4. Step 4: Simplify right side
   13,128x = 150,806,050.56
5. Step 5: Solve for x
   x = 150,806,050.56/13,128
6. Step 6: Final answer
   x = 11,487.36