Finding the Fourth Proportional to 100.31, 150.15 and 83.91

Step by Step Solution

1. Step 1: Write the proportion equation
   100.31 : 150.15 = 83.91 : x
2. Step 2: Convert to fraction form
   100.31/150.15 = 83.91/x
3. Step 3: Cross multiply
   100.31x = 150.15 × 83.91
4. Step 4: Simplify right side
   100.31x = 12,599.09
5. Step 5: Solve for x
   x = 12,599.09/100.31
6. Step 6: Final answer
   x = 125.60