Finding the Fourth Proportional to 42,080.13, 63,109.35 and 12,491.28

Step by Step Solution

1. Step 1: Write the proportion equation
   42,080.13 : 63,109.35 = 12,491.28 : x
2. Step 2: Convert to fraction form
   42,080.13/63,109.35 = 12,491.28/x
3. Step 3: Cross multiply
   42,080.13x = 63,109.35 × 12,491.28
4. Step 4: Simplify right side
   42,080.13x = 788,316,561.47
5. Step 5: Solve for x
   x = 788,316,561.47/42,080.13
6. Step 6: Final answer
   x = 18,733.70