Finding the Fourth Proportional to 40,978.80, 61,482.72 and 13,276.80

Step by Step Solution

1. Step 1: Write the proportion equation
   40,978.80 : 61,482.72 = 13,276.80 : x
2. Step 2: Convert to fraction form
   40,978.80/61,482.72 = 13,276.80/x
3. Step 3: Cross multiply
   40,978.80x = 61,482.72 × 13,276.80
4. Step 4: Simplify right side
   40,978.80x = 816,293,776.90
5. Step 5: Solve for x
   x = 816,293,776.90/40,978.80
6. Step 6: Final answer
   x = 19,919.90