Finding the Fourth Proportional to 42,888.55, 64,310.88 and 17,921.78

Step by Step Solution

1. Step 1: Write the proportion equation
   42,888.55 : 64,310.88 = 17,921.78 : x
2. Step 2: Convert to fraction form
   42,888.55/64,310.88 = 17,921.78/x
3. Step 3: Cross multiply
   42,888.55x = 64,310.88 × 17,921.78
4. Step 4: Simplify right side
   42,888.55x = 1,152,565,442.97
5. Step 5: Solve for x
   x = 1,152,565,442.97/42,888.55
6. Step 6: Final answer
   x = 26,873.50