Finding the Fourth Proportional to 13,311, 19,979.72 and 7,071.06

Step by Step Solution

1. Step 1: Write the proportion equation
   13,311 : 19,979.72 = 7,071.06 : x
2. Step 2: Convert to fraction form
   13,311/19,979.72 = 7,071.06/x
3. Step 3: Cross multiply
   13,311x = 19,979.72 × 7,071.06
4. Step 4: Simplify right side
   13,311x = 141,277,798.90
5. Step 5: Solve for x
   x = 141,277,798.90/13,311
6. Step 6: Final answer
   x = 10,613.61