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Finding the Fourth Proportional to 645.48, 890.82 and 393.39

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Solution

The fourth proportional to 645.48, 890.82 and 393.39 is: 542.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.48 : 890.82 = 393.39 : x
  2. Step 2: Convert to fraction form
    645.48/890.82 = 393.39/x
  3. Step 3: Cross multiply
    645.48x = 890.82 × 393.39
  4. Step 4: Simplify right side
    645.48x = 350,440.79
  5. Step 5: Solve for x
    x = 350,440.79/645.48
  6. Step 6: Final answer
    x = 542.92

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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.