Finding the Fourth Proportional to 13,145.86, 18,141.75 and 7,178.05

Step by Step Solution

1. Step 1: Write the proportion equation
   13,145.86 : 18,141.75 = 7,178.05 : x
2. Step 2: Convert to fraction form
   13,145.86/18,141.75 = 7,178.05/x
3. Step 3: Cross multiply
   13,145.86x = 18,141.75 × 7,178.05
4. Step 4: Simplify right side
   13,145.86x = 130,222,388.59
5. Step 5: Solve for x
   x = 130,222,388.59/13,145.86
6. Step 6: Final answer
   x = 9,905.96