Finding the Fourth Proportional to 12,613.30, 18,914.55 and 5,215.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,613.30 : 18,914.55 = 5,215.30 : x
2. Step 2: Convert to fraction form
   12,613.30/18,914.55 = 5,215.30/x
3. Step 3: Cross multiply
   12,613.30x = 18,914.55 × 5,215.30
4. Step 4: Simplify right side
   12,613.30x = 98,645,052.62
5. Step 5: Solve for x
   x = 98,645,052.62/12,613.30
6. Step 6: Final answer
   x = 7,820.72