Finding the Fourth Proportional to 9,139.50, 12,613.05 and 5,161.05

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.50 : 12,613.05 = 5,161.05 : x
2. Step 2: Convert to fraction form
   9,139.50/12,613.05 = 5,161.05/x
3. Step 3: Cross multiply
   9,139.50x = 12,613.05 × 5,161.05
4. Step 4: Simplify right side
   9,139.50x = 65,096,581.70
5. Step 5: Solve for x
   x = 65,096,581.70/9,139.50
6. Step 6: Final answer
   x = 7,122.55