Finding the Third Proportional to 129.56 and 279.31

Step by Step Solution

1. Step 1: Write the proportion equation
   129.56 : 279.31 = 279.31 : x
2. Step 2: Convert to fraction form
   129.56/279.31 = 279.31/x
3. Step 3: Cross multiply
   129.56x = 279.31 × 279.31
4. Step 4: Simplify right side
   129.56x = 78,015.47
5. Step 5: Solve for x
   x = 78,015.47/129.56
6. Step 6: Final answer
   x = 602.15