Finding the Fourth Proportional to 99.50, 137.35 and 65.10

Step by Step Solution

1. Step 1: Write the proportion equation
   99.50 : 137.35 = 65.10 : x
2. Step 2: Convert to fraction form
   99.50/137.35 = 65.10/x
3. Step 3: Cross multiply
   99.50x = 137.35 × 65.10
4. Step 4: Simplify right side
   99.50x = 8,941.49
5. Step 5: Solve for x
   x = 8,941.49/99.50
6. Step 6: Final answer
   x = 89.86