Finding the Fourth Proportional to 86.61, 129.56 and 59.50

Step by Step Solution

1. Step 1: Write the proportion equation
   86.61 : 129.56 = 59.50 : x
2. Step 2: Convert to fraction form
   86.61/129.56 = 59.50/x
3. Step 3: Cross multiply
   86.61x = 129.56 × 59.50
4. Step 4: Simplify right side
   86.61x = 7,708.17
5. Step 5: Solve for x
   x = 7,708.17/86.61
6. Step 6: Final answer
   x = 89.00