Finding the Fourth Proportional to 13,978.01, 20,970.66 and 5,213

Step by Step Solution

1. Step 1: Write the proportion equation
   13,978.01 : 20,970.66 = 5,213 : x
2. Step 2: Convert to fraction form
   13,978.01/20,970.66 = 5,213/x
3. Step 3: Cross multiply
   13,978.01x = 20,970.66 × 5,213
4. Step 4: Simplify right side
   13,978.01x = 109,320,050.58
5. Step 5: Solve for x
   x = 109,320,050.58/13,978.01
6. Step 6: Final answer
   x = 7,820.86