Finding the Third Proportional to 1,678.78 and 3,577.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,678.78 : 3,577.78 = 3,577.78 : x
2. Step 2: Convert to fraction form
   1,678.78/3,577.78 = 3,577.78/x
3. Step 3: Cross multiply
   1,678.78x = 3,577.78 × 3,577.78
4. Step 4: Simplify right side
   1,678.78x = 12,800,518.67
5. Step 5: Solve for x
   x = 12,800,518.67/1,678.78
6. Step 6: Final answer
   x = 7,624.89