Finding the Fourth Proportional to 78.17, 117.51 and 72.82

Step by Step Solution

1. Step 1: Write the proportion equation
   78.17 : 117.51 = 72.82 : x
2. Step 2: Convert to fraction form
   78.17/117.51 = 72.82/x
3. Step 3: Cross multiply
   78.17x = 117.51 × 72.82
4. Step 4: Simplify right side
   78.17x = 8,557.49
5. Step 5: Solve for x
   x = 8,557.49/78.17
6. Step 6: Final answer
   x = 109.47