Finding the Fourth Proportional to 99.39, 137.00 and 78.63

Step by Step Solution

1. Step 1: Write the proportion equation
   99.39 : 137.00 = 78.63 : x
2. Step 2: Convert to fraction form
   99.39/137.00 = 78.63/x
3. Step 3: Cross multiply
   99.39x = 137.00 × 78.63
4. Step 4: Simplify right side
   99.39x = 10,771.92
5. Step 5: Solve for x
   x = 10,771.92/99.39
6. Step 6: Final answer
   x = 108.38