Finding the Third Proportional to 109.78 and 253.88

Step by Step Solution

1. Step 1: Write the proportion equation
   109.78 : 253.88 = 253.88 : x
2. Step 2: Convert to fraction form
   109.78/253.88 = 253.88/x
3. Step 3: Cross multiply
   109.78x = 253.88 × 253.88
4. Step 4: Simplify right side
   109.78x = 64,452.52
5. Step 5: Solve for x
   x = 64,452.52/109.78
6. Step 6: Final answer
   x = 587.10