Finding the Fourth Proportional to 28,620.77, 42,923.52 and 20,276.15

Step by Step Solution

1. Step 1: Write the proportion equation
   28,620.77 : 42,923.52 = 20,276.15 : x
2. Step 2: Convert to fraction form
   28,620.77/42,923.52 = 20,276.15/x
3. Step 3: Cross multiply
   28,620.77x = 42,923.52 × 20,276.15
4. Step 4: Simplify right side
   28,620.77x = 870,323,515.43
5. Step 5: Solve for x
   x = 870,323,515.43/28,620.77
6. Step 6: Final answer
   x = 30,408.81