Finding the Fourth Proportional to 100.59, 138.81 and 59.15

Step by Step Solution

1. Step 1: Write the proportion equation
   100.59 : 138.81 = 59.15 : x
2. Step 2: Convert to fraction form
   100.59/138.81 = 59.15/x
3. Step 3: Cross multiply
   100.59x = 138.81 × 59.15
4. Step 4: Simplify right side
   100.59x = 8,210.61
5. Step 5: Solve for x
   x = 8,210.61/100.59
6. Step 6: Final answer
   x = 81.63