Finding the Third Proportional to 42,978.50 and 66,411.75

Step by Step Solution

1. Step 1: Write the proportion equation
   42,978.50 : 66,411.75 = 66,411.75 : x
2. Step 2: Convert to fraction form
   42,978.50/66,411.75 = 66,411.75/x
3. Step 3: Cross multiply
   42,978.50x = 66,411.75 × 66,411.75
4. Step 4: Simplify right side
   42,978.50x = 4,410,520,538.06
5. Step 5: Solve for x
   x = 4,410,520,538.06/42,978.50
6. Step 6: Final answer
   x = 102,621.56