Finding the Fourth Proportional to 28,016.64, 42,018.88 and 17,991.28

Step by Step Solution

1. Step 1: Write the proportion equation
   28,016.64 : 42,018.88 = 17,991.28 : x
2. Step 2: Convert to fraction form
   28,016.64/42,018.88 = 17,991.28/x
3. Step 3: Cross multiply
   28,016.64x = 42,018.88 × 17,991.28
4. Step 4: Simplify right side
   28,016.64x = 755,973,435.37
5. Step 5: Solve for x
   x = 755,973,435.37/28,016.64
6. Step 6: Final answer
   x = 26,983.02