Finding the Fourth Proportional to 42,980.10, 64,467.18 and 13,395.12

Step by Step Solution

1. Step 1: Write the proportion equation
   42,980.10 : 64,467.18 = 13,395.12 : x
2. Step 2: Convert to fraction form
   42,980.10/64,467.18 = 13,395.12/x
3. Step 3: Cross multiply
   42,980.10x = 64,467.18 × 13,395.12
4. Step 4: Simplify right side
   42,980.10x = 863,545,612.16
5. Step 5: Solve for x
   x = 863,545,612.16/42,980.10
6. Step 6: Final answer
   x = 20,091.75