Finding the Fourth Proportional to 99.43, 137.06 and 78.68

Step by Step Solution

1. Step 1: Write the proportion equation
   99.43 : 137.06 = 78.68 : x
2. Step 2: Convert to fraction form
   99.43/137.06 = 78.68/x
3. Step 3: Cross multiply
   99.43x = 137.06 × 78.68
4. Step 4: Simplify right side
   99.43x = 10,782.80
5. Step 5: Solve for x
   x = 10,782.80/99.43
6. Step 6: Final answer
   x = 108.45