Finding the Fourth Proportional to 28,245.28, 42,381.84 and 19,978.42

Step by Step Solution

1. Step 1: Write the proportion equation
   28,245.28 : 42,381.84 = 19,978.42 : x
2. Step 2: Convert to fraction form
   28,245.28/42,381.84 = 19,978.42/x
3. Step 3: Cross multiply
   28,245.28x = 42,381.84 × 19,978.42
4. Step 4: Simplify right side
   28,245.28x = 846,722,199.89
5. Step 5: Solve for x
   x = 846,722,199.89/28,245.28
6. Step 6: Final answer
   x = 29,977.48