Finding the Fourth Proportional to 9,139.74, 12,613.42 and 5,159.40

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139.74 : 12,613.42 = 5,159.40 : x
2. Step 2: Convert to fraction form
   9,139.74/12,613.42 = 5,159.40/x
3. Step 3: Cross multiply
   9,139.74x = 12,613.42 × 5,159.40
4. Step 4: Simplify right side
   9,139.74x = 65,077,679.15
5. Step 5: Solve for x
   x = 65,077,679.15/9,139.74
6. Step 6: Final answer
   x = 7,120.30