Finding the Fourth Proportional to 100.02, 137.86 and 91.31

Step by Step Solution

1. Step 1: Write the proportion equation
   100.02 : 137.86 = 91.31 : x
2. Step 2: Convert to fraction form
   100.02/137.86 = 91.31/x
3. Step 3: Cross multiply
   100.02x = 137.86 × 91.31
4. Step 4: Simplify right side
   100.02x = 12,588.37
5. Step 5: Solve for x
   x = 12,588.37/100.02
6. Step 6: Final answer
   x = 125.85