Finding the Fourth Proportional to 11,921.55, 17,870.01 and 7,769.67

Step by Step Solution

1. Step 1: Write the proportion equation
   11,921.55 : 17,870.01 = 7,769.67 : x
2. Step 2: Convert to fraction form
   11,921.55/17,870.01 = 7,769.67/x
3. Step 3: Cross multiply
   11,921.55x = 17,870.01 × 7,769.67
4. Step 4: Simplify right side
   11,921.55x = 138,844,080.60
5. Step 5: Solve for x
   x = 138,844,080.60/11,921.55
6. Step 6: Final answer
   x = 11,646.48