Finding the Fourth Proportional to 42,938.90, 64,400.16 and 13,357.10

Step by Step Solution

1. Step 1: Write the proportion equation
   42,938.90 : 64,400.16 = 13,357.10 : x
2. Step 2: Convert to fraction form
   42,938.90/64,400.16 = 13,357.10/x
3. Step 3: Cross multiply
   42,938.90x = 64,400.16 × 13,357.10
4. Step 4: Simplify right side
   42,938.90x = 860,199,377.14
5. Step 5: Solve for x
   x = 860,199,377.14/42,938.90
6. Step 6: Final answer
   x = 20,033.10