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Finding the Fourth Proportional to 765.21, 1,147.82 and 643.10

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Solution

The fourth proportional to 765.21, 1,147.82 and 643.10 is: 964.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    765.21 : 1,147.82 = 643.10 : x
  2. Step 2: Convert to fraction form
    765.21/1,147.82 = 643.10/x
  3. Step 3: Cross multiply
    765.21x = 1,147.82 × 643.10
  4. Step 4: Simplify right side
    765.21x = 738,163.04
  5. Step 5: Solve for x
    x = 738,163.04/765.21
  6. Step 6: Final answer
    x = 964.65

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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.