Finding the Fourth Proportional to 42,780.41, 64,176.65 and 13,200.65

Step by Step Solution

1. Step 1: Write the proportion equation
   42,780.41 : 64,176.65 = 13,200.65 : x
2. Step 2: Convert to fraction form
   42,780.41/64,176.65 = 13,200.65/x
3. Step 3: Cross multiply
   42,780.41x = 64,176.65 × 13,200.65
4. Step 4: Simplify right side
   42,780.41x = 847,173,494.82
5. Step 5: Solve for x
   x = 847,173,494.82/42,780.41
6. Step 6: Final answer
   x = 19,802.84