Finding the Fourth Proportional to 100.00, 138.03 and 89.61

Step by Step Solution

1. Step 1: Write the proportion equation
   100.00 : 138.03 = 89.61 : x
2. Step 2: Convert to fraction form
   100.00/138.03 = 89.61/x
3. Step 3: Cross multiply
   100.00x = 138.03 × 89.61
4. Step 4: Simplify right side
   100.00x = 12,369.81
5. Step 5: Solve for x
   x = 12,369.81/100.00
6. Step 6: Final answer
   x = 123.70