Finding the Fourth Proportional to 42,818.38, 64,233.63 and 13,238.80

Step by Step Solution

1. Step 1: Write the proportion equation
   42,818.38 : 64,233.63 = 13,238.80 : x
2. Step 2: Convert to fraction form
   42,818.38/64,233.63 = 13,238.80/x
3. Step 3: Cross multiply
   42,818.38x = 64,233.63 × 13,238.80
4. Step 4: Simplify right side
   42,818.38x = 850,376,180.84
5. Step 5: Solve for x
   x = 850,376,180.84/42,818.38
6. Step 6: Final answer
   x = 19,860.07