Finding the Fourth Proportional to 100.89, 139.27 and 64.10

Step by Step Solution

1. Step 1: Write the proportion equation
   100.89 : 139.27 = 64.10 : x
2. Step 2: Convert to fraction form
   100.89/139.27 = 64.10/x
3. Step 3: Cross multiply
   100.89x = 139.27 × 64.10
4. Step 4: Simplify right side
   100.89x = 8,926.89
5. Step 5: Solve for x
   x = 8,926.89/100.89
6. Step 6: Final answer
   x = 88.48