Finding the Fourth Proportional to 66,618.42, 91,974.22 and 63,421.50

Step by Step Solution

1. Step 1: Write the proportion equation
   66,618.42 : 91,974.22 = 63,421.50 : x
2. Step 2: Convert to fraction form
   66,618.42/91,974.22 = 63,421.50/x
3. Step 3: Cross multiply
   66,618.42x = 91,974.22 × 63,421.50
4. Step 4: Simplify right side
   66,618.42x = 5,833,142,993.73
5. Step 5: Solve for x
   x = 5,833,142,993.73/66,618.42
6. Step 6: Final answer
   x = 87,560.51