Finding the Fourth Proportional to 42,716.72, 64,088.78 and 20,531.70

Step by Step Solution

1. Step 1: Write the proportion equation
   42,716.72 : 64,088.78 = 20,531.70 : x
2. Step 2: Convert to fraction form
   42,716.72/64,088.78 = 20,531.70/x
3. Step 3: Cross multiply
   42,716.72x = 64,088.78 × 20,531.70
4. Step 4: Simplify right side
   42,716.72x = 1,315,851,604.33
5. Step 5: Solve for x
   x = 1,315,851,604.33/42,716.72
6. Step 6: Final answer
   x = 30,804.13