Finding the Fourth Proportional to 42,573.82, 63,870.66 and 12,991.60

Step by Step Solution

1. Step 1: Write the proportion equation
   42,573.82 : 63,870.66 = 12,991.60 : x
2. Step 2: Convert to fraction form
   42,573.82/63,870.66 = 12,991.60/x
3. Step 3: Cross multiply
   42,573.82x = 63,870.66 × 12,991.60
4. Step 4: Simplify right side
   42,573.82x = 829,782,066.46
5. Step 5: Solve for x
   x = 829,782,066.46/42,573.82
6. Step 6: Final answer
   x = 19,490.43