Finding the Fourth Proportional to 42,867.60, 64,307.43 and 13,287.72

Step by Step Solution

1. Step 1: Write the proportion equation
   42,867.60 : 64,307.43 = 13,287.72 : x
2. Step 2: Convert to fraction form
   42,867.60/64,307.43 = 13,287.72/x
3. Step 3: Cross multiply
   42,867.60x = 64,307.43 × 13,287.72
4. Step 4: Simplify right side
   42,867.60x = 854,499,123.76
5. Step 5: Solve for x
   x = 854,499,123.76/42,867.60
6. Step 6: Final answer
   x = 19,933.45