Finding the Fourth Proportional to 12,678.64, 19,005.18 and 5,287.18

Step by Step Solution

1. Step 1: Write the proportion equation
   12,678.64 : 19,005.18 = 5,287.18 : x
2. Step 2: Convert to fraction form
   12,678.64/19,005.18 = 5,287.18/x
3. Step 3: Cross multiply
   12,678.64x = 19,005.18 × 5,287.18
4. Step 4: Simplify right side
   12,678.64x = 100,483,807.59
5. Step 5: Solve for x
   x = 100,483,807.59/12,678.64
6. Step 6: Final answer
   x = 7,925.44