Finding the Fourth Proportional to 90.65, 135.99 and 42.59

Step by Step Solution

1. Step 1: Write the proportion equation
   90.65 : 135.99 = 42.59 : x
2. Step 2: Convert to fraction form
   90.65/135.99 = 42.59/x
3. Step 3: Cross multiply
   90.65x = 135.99 × 42.59
4. Step 4: Simplify right side
   90.65x = 5,791.13
5. Step 5: Solve for x
   x = 5,791.13/90.65
6. Step 6: Final answer
   x = 63.89