Finding the Fourth Proportional to 12,665.60, 18,988.14 and 5,275.59

Step by Step Solution

1. Step 1: Write the proportion equation
   12,665.60 : 18,988.14 = 5,275.59 : x
2. Step 2: Convert to fraction form
   12,665.60/18,988.14 = 5,275.59/x
3. Step 3: Cross multiply
   12,665.60x = 18,988.14 × 5,275.59
4. Step 4: Simplify right side
   12,665.60x = 100,173,584.88
5. Step 5: Solve for x
   x = 100,173,584.88/12,665.60
6. Step 6: Final answer
   x = 7,909.11