Finding the Fourth Proportional to 13,245.16, 18,279.59 and 7,578.78

Step by Step Solution

1. Step 1: Write the proportion equation
   13,245.16 : 18,279.59 = 7,578.78 : x
2. Step 2: Convert to fraction form
   13,245.16/18,279.59 = 7,578.78/x
3. Step 3: Cross multiply
   13,245.16x = 18,279.59 × 7,578.78
4. Step 4: Simplify right side
   13,245.16x = 138,536,991.10
5. Step 5: Solve for x
   x = 138,536,991.10/13,245.16
6. Step 6: Final answer
   x = 10,459.44