Finding the Third Proportional to 385.78 and 549.56

Step by Step Solution

1. Step 1: Write the proportion equation
   385.78 : 549.56 = 549.56 : x
2. Step 2: Convert to fraction form
   385.78/549.56 = 549.56/x
3. Step 3: Cross multiply
   385.78x = 549.56 × 549.56
4. Step 4: Simplify right side
   385.78x = 302,018.94
5. Step 5: Solve for x
   x = 302,018.94/385.78
6. Step 6: Final answer
   x = 782.88