Finding the Fourth Proportional to 65,775.72, 91,382.76 and 64,988.40

Step by Step Solution

1. Step 1: Write the proportion equation
   65,775.72 : 91,382.76 = 64,988.40 : x
2. Step 2: Convert to fraction form
   65,775.72/91,382.76 = 64,988.40/x
3. Step 3: Cross multiply
   65,775.72x = 91,382.76 × 64,988.40
4. Step 4: Simplify right side
   65,775.72x = 5,938,819,359.98
5. Step 5: Solve for x
   x = 5,938,819,359.98/65,775.72
6. Step 6: Final answer
   x = 90,288.93