Finding the Third Proportional to 678.38 and 1,123.69

Step by Step Solution

1. Step 1: Write the proportion equation
   678.38 : 1,123.69 = 1,123.69 : x
2. Step 2: Convert to fraction form
   678.38/1,123.69 = 1,123.69/x
3. Step 3: Cross multiply
   678.38x = 1,123.69 × 1,123.69
4. Step 4: Simplify right side
   678.38x = 1,262,673.60
5. Step 5: Solve for x
   x = 1,262,673.60/678.38
6. Step 6: Final answer
   x = 1,861.32