Finding the Fourth Proportional to 28,656.89, 42,988.06 and 11,128.08

Step by Step Solution

1. Step 1: Write the proportion equation
   28,656.89 : 42,988.06 = 11,128.08 : x
2. Step 2: Convert to fraction form
   28,656.89/42,988.06 = 11,128.08/x
3. Step 3: Cross multiply
   28,656.89x = 42,988.06 × 11,128.08
4. Step 4: Simplify right side
   28,656.89x = 478,374,570.72
5. Step 5: Solve for x
   x = 478,374,570.72/28,656.89
6. Step 6: Final answer
   x = 16,693.18