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Finding the Fourth Proportional to 687.15, 947.70 and 490.77

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Solution

The fourth proportional to 687.15, 947.70 and 490.77 is: 676.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.15 : 947.70 = 490.77 : x
  2. Step 2: Convert to fraction form
    687.15/947.70 = 490.77/x
  3. Step 3: Cross multiply
    687.15x = 947.70 × 490.77
  4. Step 4: Simplify right side
    687.15x = 465,102.73
  5. Step 5: Solve for x
    x = 465,102.73/687.15
  6. Step 6: Final answer
    x = 676.86

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Half scale
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Double scale
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1.5x scale

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.