Finding the Fourth Proportional to 76,781.47, 105,961.70 and 42,790

Step by Step Solution

1. Step 1: Write the proportion equation
   76,781.47 : 105,961.70 = 42,790 : x
2. Step 2: Convert to fraction form
   76,781.47/105,961.70 = 42,790/x
3. Step 3: Cross multiply
   76,781.47x = 105,961.70 × 42,790
4. Step 4: Simplify right side
   76,781.47x = 4,534,101,143
5. Step 5: Solve for x
   x = 4,534,101,143/76,781.47
6. Step 6: Final answer
   x = 59,052.02