Finding the Fourth Proportional to 99.93, 137.88 and 78.06

Step by Step Solution

1. Step 1: Write the proportion equation
   99.93 : 137.88 = 78.06 : x
2. Step 2: Convert to fraction form
   99.93/137.88 = 78.06/x
3. Step 3: Cross multiply
   99.93x = 137.88 × 78.06
4. Step 4: Simplify right side
   99.93x = 10,762.91
5. Step 5: Solve for x
   x = 10,762.91/99.93
6. Step 6: Final answer
   x = 107.70