Finding the Third Proportional to 42,210 and 64,800

Step by Step Solution

1. Step 1: Write the proportion equation
   42,210 : 64,800 = 64,800 : x
2. Step 2: Convert to fraction form
   42,210/64,800 = 64,800/x
3. Step 3: Cross multiply
   42,210x = 64,800 × 64,800
4. Step 4: Simplify right side
   42,210x = 4,199,040,000
5. Step 5: Solve for x
   x = 4,199,040,000/42,210
6. Step 6: Final answer
   x = 99,479.74