Finding the Fourth Proportional to 42,856.74, 64,272.69 and 12,869.76

Step by Step Solution

1. Step 1: Write the proportion equation
   42,856.74 : 64,272.69 = 12,869.76 : x
2. Step 2: Convert to fraction form
   42,856.74/64,272.69 = 12,869.76/x
3. Step 3: Cross multiply
   42,856.74x = 64,272.69 × 12,869.76
4. Step 4: Simplify right side
   42,856.74x = 827,174,335.88
5. Step 5: Solve for x
   x = 827,174,335.88/42,856.74
6. Step 6: Final answer
   x = 19,300.92