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Finding the Fourth Proportional to 717.77, 990.46 and 398.75

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Solution

The fourth proportional to 717.77, 990.46 and 398.75 is: 550.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    717.77 : 990.46 = 398.75 : x
  2. Step 2: Convert to fraction form
    717.77/990.46 = 398.75/x
  3. Step 3: Cross multiply
    717.77x = 990.46 × 398.75
  4. Step 4: Simplify right side
    717.77x = 394,945.93
  5. Step 5: Solve for x
    x = 394,945.93/717.77
  6. Step 6: Final answer
    x = 550.24

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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.