Finding the Fourth Proportional to 128,577.32, 177,434.72 and 71,990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   128,577.32 : 177,434.72 = 71,990.72 : x
2. Step 2: Convert to fraction form
   128,577.32/177,434.72 = 71,990.72/x
3. Step 3: Cross multiply
   128,577.32x = 177,434.72 × 71,990.72
4. Step 4: Simplify right side
   128,577.32x = 12,773,653,245.80
5. Step 5: Solve for x
   x = 12,773,653,245.80/128,577.32
6. Step 6: Final answer
   x = 99,346.08