Finding the Third Proportional to 278.50 and 336.50

Step by Step Solution

1. Step 1: Write the proportion equation
   278.50 : 336.50 = 336.50 : x
2. Step 2: Convert to fraction form
   278.50/336.50 = 336.50/x
3. Step 3: Cross multiply
   278.50x = 336.50 × 336.50
4. Step 4: Simplify right side
   278.50x = 113,232.25
5. Step 5: Solve for x
   x = 113,232.25/278.50
6. Step 6: Final answer
   x = 406.58