Finding the Fourth Proportional to 128,568.72, 177,423.44 and 71,980.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128,568.72 : 177,423.44 = 71,980.72 : x
2. Step 2: Convert to fraction form
   128,568.72/177,423.44 = 71,980.72/x
3. Step 3: Cross multiply
   128,568.72x = 177,423.44 × 71,980.72
4. Step 4: Simplify right side
   128,568.72x = 12,771,066,956.08
5. Step 5: Solve for x
   x = 12,771,066,956.08/128,568.72
6. Step 6: Final answer
   x = 99,332.61