Finding the Fourth Proportional to 9,120.94, 12,588.72 and 5,142.12

Step by Step Solution

1. Step 1: Write the proportion equation
   9,120.94 : 12,588.72 = 5,142.12 : x
2. Step 2: Convert to fraction form
   9,120.94/12,588.72 = 5,142.12/x
3. Step 3: Cross multiply
   9,120.94x = 12,588.72 × 5,142.12
4. Step 4: Simplify right side
   9,120.94x = 64,732,642.40
5. Step 5: Solve for x
   x = 64,732,642.40/9,120.94
6. Step 6: Final answer
   x = 7,097.15