Finding the Fourth Proportional to 82.50, 123.75 and 64.50

Step by Step Solution

1. Step 1: Write the proportion equation
   82.50 : 123.75 = 64.50 : x
2. Step 2: Convert to fraction form
   82.50/123.75 = 64.50/x
3. Step 3: Cross multiply
   82.50x = 123.75 × 64.50
4. Step 4: Simplify right side
   82.50x = 7,981.88
5. Step 5: Solve for x
   x = 7,981.88/82.50
6. Step 6: Final answer
   x = 96.75