Finding the Fourth Proportional to 16,978.51, 25,457.79 and 5,128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   16,978.51 : 25,457.79 = 5,128.72 : x
2. Step 2: Convert to fraction form
   16,978.51/25,457.79 = 5,128.72/x
3. Step 3: Cross multiply
   16,978.51x = 25,457.79 × 5,128.72
4. Step 4: Simplify right side
   16,978.51x = 130,565,832.32
5. Step 5: Solve for x
   x = 130,565,832.32/16,978.51
6. Step 6: Final answer
   x = 7,690.06