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Finding the Fourth Proportional to 840.70, 1,261.05 and 255.70

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Solution

The fourth proportional to 840.70, 1,261.05 and 255.70 is: 383.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.70 : 1,261.05 = 255.70 : x
  2. Step 2: Convert to fraction form
    840.70/1,261.05 = 255.70/x
  3. Step 3: Cross multiply
    840.70x = 1,261.05 × 255.70
  4. Step 4: Simplify right side
    840.70x = 322,446.37
  5. Step 5: Solve for x
    x = 322,446.37/840.70
  6. Step 6: Final answer
    x = 383.55

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Double scale
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Similar ratio
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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.