Finding the Fourth Proportional to 91.90, 137.71 and 59.31

Step by Step Solution

1. Step 1: Write the proportion equation
   91.90 : 137.71 = 59.31 : x
2. Step 2: Convert to fraction form
   91.90/137.71 = 59.31/x
3. Step 3: Cross multiply
   91.90x = 137.71 × 59.31
4. Step 4: Simplify right side
   91.90x = 8,167.58
5. Step 5: Solve for x
   x = 8,167.58/91.90
6. Step 6: Final answer
   x = 88.87