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Finding the Fourth Proportional to 1,292.80, 1,939.08 and 427

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Solution

The fourth proportional to 1,292.80, 1,939.08 and 427 is: 640.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.80 : 1,939.08 = 427 : x
  2. Step 2: Convert to fraction form
    1,292.80/1,939.08 = 427/x
  3. Step 3: Cross multiply
    1,292.80x = 1,939.08 × 427
  4. Step 4: Simplify right side
    1,292.80x = 827,987.16
  5. Step 5: Solve for x
    x = 827,987.16/1,292.80
  6. Step 6: Final answer
    x = 640.46

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Double scale
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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.