Finding the Third Proportional to 78,345.50 and 176,978.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78,345.50 : 176,978.50 = 176,978.50 : x
2. Step 2: Convert to fraction form
   78,345.50/176,978.50 = 176,978.50/x
3. Step 3: Cross multiply
   78,345.50x = 176,978.50 × 176,978.50
4. Step 4: Simplify right side
   78,345.50x = 31,321,389,462.25
5. Step 5: Solve for x
   x = 31,321,389,462.25/78,345.50
6. Step 6: Final answer
   x = 399,785.43