Finding the Fourth Proportional to 42,981.98, 64,479.44 and 13,402.13

Step by Step Solution

1. Step 1: Write the proportion equation
   42,981.98 : 64,479.44 = 13,402.13 : x
2. Step 2: Convert to fraction form
   42,981.98/64,479.44 = 13,402.13/x
3. Step 3: Cross multiply
   42,981.98x = 64,479.44 × 13,402.13
4. Step 4: Simplify right side
   42,981.98x = 864,161,548.32
5. Step 5: Solve for x
   x = 864,161,548.32/42,981.98
6. Step 6: Final answer
   x = 20,105.21