Finding the Fourth Proportional to 99.83, 137.28 and 79.91

Step by Step Solution

1. Step 1: Write the proportion equation
   99.83 : 137.28 = 79.91 : x
2. Step 2: Convert to fraction form
   99.83/137.28 = 79.91/x
3. Step 3: Cross multiply
   99.83x = 137.28 × 79.91
4. Step 4: Simplify right side
   99.83x = 10,969.87
5. Step 5: Solve for x
   x = 10,969.87/99.83
6. Step 6: Final answer
   x = 109.89