Finding the Third Proportional to 274.50 and 391.50

Step by Step Solution

1. Step 1: Write the proportion equation
   274.50 : 391.50 = 391.50 : x
2. Step 2: Convert to fraction form
   274.50/391.50 = 391.50/x
3. Step 3: Cross multiply
   274.50x = 391.50 × 391.50
4. Step 4: Simplify right side
   274.50x = 153,272.25
5. Step 5: Solve for x
   x = 153,272.25/274.50
6. Step 6: Final answer
   x = 558.37