Finding the Fourth Proportional to 100.82, 139.17 and 65.87

Step by Step Solution

1. Step 1: Write the proportion equation
   100.82 : 139.17 = 65.87 : x
2. Step 2: Convert to fraction form
   100.82/139.17 = 65.87/x
3. Step 3: Cross multiply
   100.82x = 139.17 × 65.87
4. Step 4: Simplify right side
   100.82x = 9,167.23
5. Step 5: Solve for x
   x = 9,167.23/100.82
6. Step 6: Final answer
   x = 90.93