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Finding the Fourth Proportional to 982.78, 1,355.79 and 668.55

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Solution

The fourth proportional to 982.78, 1,355.79 and 668.55 is: 922.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    982.78 : 1,355.79 = 668.55 : x
  2. Step 2: Convert to fraction form
    982.78/1,355.79 = 668.55/x
  3. Step 3: Cross multiply
    982.78x = 1,355.79 × 668.55
  4. Step 4: Simplify right side
    982.78x = 906,417.24
  5. Step 5: Solve for x
    x = 906,417.24/982.78
  6. Step 6: Final answer
    x = 922.30

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.