Finding the Fourth Proportional to 12,886.60, 19,429.30 and 12,806.64

Step by Step Solution

1. Step 1: Write the proportion equation
   12,886.60 : 19,429.30 = 12,806.64 : x
2. Step 2: Convert to fraction form
   12,886.60/19,429.30 = 12,806.64/x
3. Step 3: Cross multiply
   12,886.60x = 19,429.30 × 12,806.64
4. Step 4: Simplify right side
   12,886.60x = 248,824,050.55
5. Step 5: Solve for x
   x = 248,824,050.55/12,886.60
6. Step 6: Final answer
   x = 19,308.74