Finding the Third Proportional to 56.25 and 85.31

Step by Step Solution

1. Step 1: Write the proportion equation
   56.25 : 85.31 = 85.31 : x
2. Step 2: Convert to fraction form
   56.25/85.31 = 85.31/x
3. Step 3: Cross multiply
   56.25x = 85.31 × 85.31
4. Step 4: Simplify right side
   56.25x = 7,278.22
5. Step 5: Solve for x
   x = 7,278.22/56.25
6. Step 6: Final answer
   x = 129.39