Finding the Third Proportional to 42.25 and 78.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42.25 : 78.50 = 78.50 : x
2. Step 2: Convert to fraction form
   42.25/78.50 = 78.50/x
3. Step 3: Cross multiply
   42.25x = 78.50 × 78.50
4. Step 4: Simplify right side
   42.25x = 6,162.25
5. Step 5: Solve for x
   x = 6,162.25/42.25
6. Step 6: Final answer
   x = 145.85