Finding the Fourth Proportional to 100.87, 150.84 and 86.59

Step by Step Solution

1. Step 1: Write the proportion equation
   100.87 : 150.84 = 86.59 : x
2. Step 2: Convert to fraction form
   100.87/150.84 = 86.59/x
3. Step 3: Cross multiply
   100.87x = 150.84 × 86.59
4. Step 4: Simplify right side
   100.87x = 13,061.24
5. Step 5: Solve for x
   x = 13,061.24/100.87
6. Step 6: Final answer
   x = 129.49