Finding the Fourth Proportional to 42,980.58, 64,470.89 and 13,400.80

Step by Step Solution

1. Step 1: Write the proportion equation
   42,980.58 : 64,470.89 = 13,400.80 : x
2. Step 2: Convert to fraction form
   42,980.58/64,470.89 = 13,400.80/x
3. Step 3: Cross multiply
   42,980.58x = 64,470.89 × 13,400.80
4. Step 4: Simplify right side
   42,980.58x = 863,961,502.71
5. Step 5: Solve for x
   x = 863,961,502.71/42,980.58
6. Step 6: Final answer
   x = 20,101.21