Finding the Fourth Proportional to 1,020.56, 1,416.86 and 988.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,020.56 : 1,416.86 = 988.88 : x
2. Step 2: Convert to fraction form
   1,020.56/1,416.86 = 988.88/x
3. Step 3: Cross multiply
   1,020.56x = 1,416.86 × 988.88
4. Step 4: Simplify right side
   1,020.56x = 1,401,104.52
5. Step 5: Solve for x
   x = 1,401,104.52/1,020.56
6. Step 6: Final answer
   x = 1,372.88