Finding the Fourth Proportional to 82.61, 123.37 and 78.17

Step by Step Solution

1. Step 1: Write the proportion equation
   82.61 : 123.37 = 78.17 : x
2. Step 2: Convert to fraction form
   82.61/123.37 = 78.17/x
3. Step 3: Cross multiply
   82.61x = 123.37 × 78.17
4. Step 4: Simplify right side
   82.61x = 9,643.83
5. Step 5: Solve for x
   x = 9,643.83/82.61
6. Step 6: Final answer
   x = 116.74