Finding the Third Proportional to 222.75 and 520.31

Step by Step Solution

1. Step 1: Write the proportion equation
   222.75 : 520.31 = 520.31 : x
2. Step 2: Convert to fraction form
   222.75/520.31 = 520.31/x
3. Step 3: Cross multiply
   222.75x = 520.31 × 520.31
4. Step 4: Simplify right side
   222.75x = 270,725.10
5. Step 5: Solve for x
   x = 270,725.10/222.75
6. Step 6: Final answer
   x = 1,215.38