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Finding the Fourth Proportional to 645.08, 890.21 and 551.71

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Solution

The fourth proportional to 645.08, 890.21 and 551.71 is: 761.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.08 : 890.21 = 551.71 : x
  2. Step 2: Convert to fraction form
    645.08/890.21 = 551.71/x
  3. Step 3: Cross multiply
    645.08x = 890.21 × 551.71
  4. Step 4: Simplify right side
    645.08x = 491,130.55
  5. Step 5: Solve for x
    x = 491,130.55/645.08
  6. Step 6: Final answer
    x = 761.35

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Double scale
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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.