Finding the Fourth Proportional to 100.50, 150.61 and 90.51

Step by Step Solution

1. Step 1: Write the proportion equation
   100.50 : 150.61 = 90.51 : x
2. Step 2: Convert to fraction form
   100.50/150.61 = 90.51/x
3. Step 3: Cross multiply
   100.50x = 150.61 × 90.51
4. Step 4: Simplify right side
   100.50x = 13,631.71
5. Step 5: Solve for x
   x = 13,631.71/100.50
6. Step 6: Final answer
   x = 135.64