Finding the Third Proportional to 5,287.78 and 7,681.78

Step by Step Solution

1. Step 1: Write the proportion equation
   5,287.78 : 7,681.78 = 7,681.78 : x
2. Step 2: Convert to fraction form
   5,287.78/7,681.78 = 7,681.78/x
3. Step 3: Cross multiply
   5,287.78x = 7,681.78 × 7,681.78
4. Step 4: Simplify right side
   5,287.78x = 59,009,763.17
5. Step 5: Solve for x
   x = 59,009,763.17/5,287.78
6. Step 6: Final answer
   x = 11,159.65