Finding the Fourth Proportional to 112,638.60, 155,439 and 64,890.72

Step by Step Solution

1. Step 1: Write the proportion equation
   112,638.60 : 155,439 = 64,890.72 : x
2. Step 2: Convert to fraction form
   112,638.60/155,439 = 64,890.72/x
3. Step 3: Cross multiply
   112,638.60x = 155,439 × 64,890.72
4. Step 4: Simplify right side
   112,638.60x = 10,086,548,626.08
5. Step 5: Solve for x
   x = 10,086,548,626.08/112,638.60
6. Step 6: Final answer
   x = 89,547.89