Finding the Third Proportional to 275.25 and 427.69

Step by Step Solution

1. Step 1: Write the proportion equation
   275.25 : 427.69 = 427.69 : x
2. Step 2: Convert to fraction form
   275.25/427.69 = 427.69/x
3. Step 3: Cross multiply
   275.25x = 427.69 × 427.69
4. Step 4: Simplify right side
   275.25x = 182,916.60
5. Step 5: Solve for x
   x = 182,916.60/275.25
6. Step 6: Final answer
   x = 664.55