Finding the Fourth Proportional to 42,805.89, 64,211.91 and 13,219.88

Step by Step Solution

1. Step 1: Write the proportion equation
   42,805.89 : 64,211.91 = 13,219.88 : x
2. Step 2: Convert to fraction form
   42,805.89/64,211.91 = 13,219.88/x
3. Step 3: Cross multiply
   42,805.89x = 64,211.91 × 13,219.88
4. Step 4: Simplify right side
   42,805.89x = 848,874,027.47
5. Step 5: Solve for x
   x = 848,874,027.47/42,805.89
6. Step 6: Final answer
   x = 19,830.77