Finding the Fourth Proportional to 11,817.55, 17,721.78 and 3,917.67

Step by Step Solution

1. Step 1: Write the proportion equation
   11,817.55 : 17,721.78 = 3,917.67 : x
2. Step 2: Convert to fraction form
   11,817.55/17,721.78 = 3,917.67/x
3. Step 3: Cross multiply
   11,817.55x = 17,721.78 × 3,917.67
4. Step 4: Simplify right side
   11,817.55x = 69,428,085.85
5. Step 5: Solve for x
   x = 69,428,085.85/11,817.55
6. Step 6: Final answer
   x = 5,875.00