Finding the Fourth Proportional to 28,978.56, 39,978.36 and 19,530.72

Step by Step Solution

1. Step 1: Write the proportion equation
   28,978.56 : 39,978.36 = 19,530.72 : x
2. Step 2: Convert to fraction form
   28,978.56/39,978.36 = 19,530.72/x
3. Step 3: Cross multiply
   28,978.56x = 39,978.36 × 19,530.72
4. Step 4: Simplify right side
   28,978.56x = 780,806,155.22
5. Step 5: Solve for x
   x = 780,806,155.22/28,978.56
6. Step 6: Final answer
   x = 26,944.27