Finding the Fourth Proportional to 42,913.40, 64,388.33 and 20,715.35

Step by Step Solution

1. Step 1: Write the proportion equation
   42,913.40 : 64,388.33 = 20,715.35 : x
2. Step 2: Convert to fraction form
   42,913.40/64,388.33 = 20,715.35/x
3. Step 3: Cross multiply
   42,913.40x = 64,388.33 × 20,715.35
4. Step 4: Simplify right side
   42,913.40x = 1,333,826,688.29
5. Step 5: Solve for x
   x = 1,333,826,688.29/42,913.40
6. Step 6: Final answer
   x = 31,081.82