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Finding the Fourth Proportional to 842.80, 1,265.40 and 660.40

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Solution

The fourth proportional to 842.80, 1,265.40 and 660.40 is: 991.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.80 : 1,265.40 = 660.40 : x
  2. Step 2: Convert to fraction form
    842.80/1,265.40 = 660.40/x
  3. Step 3: Cross multiply
    842.80x = 1,265.40 × 660.40
  4. Step 4: Simplify right side
    842.80x = 835,670.16
  5. Step 5: Solve for x
    x = 835,670.16/842.80
  6. Step 6: Final answer
    x = 991.54

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.