Finding the Fourth Proportional to 42,859.50, 64,330.82 and 20,688.50

Step by Step Solution

1. Step 1: Write the proportion equation
   42,859.50 : 64,330.82 = 20,688.50 : x
2. Step 2: Convert to fraction form
   42,859.50/64,330.82 = 20,688.50/x
3. Step 3: Cross multiply
   42,859.50x = 64,330.82 × 20,688.50
4. Step 4: Simplify right side
   42,859.50x = 1,330,908,169.57
5. Step 5: Solve for x
   x = 1,330,908,169.57/42,859.50
6. Step 6: Final answer
   x = 31,052.82