Finding the Fourth Proportional to 72,980.30, 109,470.72 and 20,389.70

Step by Step Solution

1. Step 1: Write the proportion equation
   72,980.30 : 109,470.72 = 20,389.70 : x
2. Step 2: Convert to fraction form
   72,980.30/109,470.72 = 20,389.70/x
3. Step 3: Cross multiply
   72,980.30x = 109,470.72 × 20,389.70
4. Step 4: Simplify right side
   72,980.30x = 2,232,075,139.58
5. Step 5: Solve for x
   x = 2,232,075,139.58/72,980.30
6. Step 6: Final answer
   x = 30,584.63