Finding the Fourth Proportional to 90.52, 135.99 and 89.10

Step by Step Solution

1. Step 1: Write the proportion equation
   90.52 : 135.99 = 89.10 : x
2. Step 2: Convert to fraction form
   90.52/135.99 = 89.10/x
3. Step 3: Cross multiply
   90.52x = 135.99 × 89.10
4. Step 4: Simplify right side
   90.52x = 12,116.71
5. Step 5: Solve for x
   x = 12,116.71/90.52
6. Step 6: Final answer
   x = 133.86