Finding the Third Proportional to 499.61 and 698.78

Step by Step Solution

1. Step 1: Write the proportion equation
   499.61 : 698.78 = 698.78 : x
2. Step 2: Convert to fraction form
   499.61/698.78 = 698.78/x
3. Step 3: Cross multiply
   499.61x = 698.78 × 698.78
4. Step 4: Simplify right side
   499.61x = 488,297.96
5. Step 5: Solve for x
   x = 488,297.96/499.61
6. Step 6: Final answer
   x = 977.37