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Finding the Fourth Proportional to 817.20, 1,128.09 and 485.73

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Solution

The fourth proportional to 817.20, 1,128.09 and 485.73 is: 670.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.20 : 1,128.09 = 485.73 : x
  2. Step 2: Convert to fraction form
    817.20/1,128.09 = 485.73/x
  3. Step 3: Cross multiply
    817.20x = 1,128.09 × 485.73
  4. Step 4: Simplify right side
    817.20x = 547,947.16
  5. Step 5: Solve for x
    x = 547,947.16/817.20
  6. Step 6: Final answer
    x = 670.52

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Double scale
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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.