Finding the Fourth Proportional to 42,770.69, 64,164.57 and 13,187.39

Step by Step Solution

1. Step 1: Write the proportion equation
   42,770.69 : 64,164.57 = 13,187.39 : x
2. Step 2: Convert to fraction form
   42,770.69/64,164.57 = 13,187.39/x
3. Step 3: Cross multiply
   42,770.69x = 64,164.57 × 13,187.39
4. Step 4: Simplify right side
   42,770.69x = 846,163,142.84
5. Step 5: Solve for x
   x = 846,163,142.84/42,770.69
6. Step 6: Final answer
   x = 19,783.72