Finding the Fourth Proportional to 1,011.42, 1,518.42 and 780.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,011.42 : 1,518.42 = 780.47 : x
2. Step 2: Convert to fraction form
   1,011.42/1,518.42 = 780.47/x
3. Step 3: Cross multiply
   1,011.42x = 1,518.42 × 780.47
4. Step 4: Simplify right side
   1,011.42x = 1,185,073.67
5. Step 5: Solve for x
   x = 1,185,073.67/1,011.42
6. Step 6: Final answer
   x = 1,171.69