Finding the Fourth Proportional to 90.59, 135.59 and 59.99

Step by Step Solution

1. Step 1: Write the proportion equation
   90.59 : 135.59 = 59.99 : x
2. Step 2: Convert to fraction form
   90.59/135.59 = 59.99/x
3. Step 3: Cross multiply
   90.59x = 135.59 × 59.99
4. Step 4: Simplify right side
   90.59x = 8,133.07
5. Step 5: Solve for x
   x = 8,133.07/90.59
6. Step 6: Final answer
   x = 89.78