Finding the Fourth Proportional to 105,840, 146,066.40 and 61,128

Step by Step Solution

1. Step 1: Write the proportion equation
   105,840 : 146,066.40 = 61,128 : x
2. Step 2: Convert to fraction form
   105,840/146,066.40 = 61,128/x
3. Step 3: Cross multiply
   105,840x = 146,066.40 × 61,128
4. Step 4: Simplify right side
   105,840x = 8,928,746,899.20
5. Step 5: Solve for x
   x = 8,928,746,899.20/105,840
6. Step 6: Final answer
   x = 84,360.80