Finding the Fourth Proportional to 128,279, 177,021.72 and 71,690.84

Step by Step Solution

1. Step 1: Write the proportion equation
   128,279 : 177,021.72 = 71,690.84 : x
2. Step 2: Convert to fraction form
   128,279/177,021.72 = 71,690.84/x
3. Step 3: Cross multiply
   128,279x = 177,021.72 × 71,690.84
4. Step 4: Simplify right side
   128,279x = 12,690,835,805.04
5. Step 5: Solve for x
   x = 12,690,835,805.04/128,279
6. Step 6: Final answer
   x = 98,931.51