Finding the Fourth Proportional to 78.62, 117.72 and 67.14

Step by Step Solution

1. Step 1: Write the proportion equation
   78.62 : 117.72 = 67.14 : x
2. Step 2: Convert to fraction form
   78.62/117.72 = 67.14/x
3. Step 3: Cross multiply
   78.62x = 117.72 × 67.14
4. Step 4: Simplify right side
   78.62x = 7,903.72
5. Step 5: Solve for x
   x = 7,903.72/78.62
6. Step 6: Final answer
   x = 100.53