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Finding the Fourth Proportional to 871.72, 1,308.18 and 641.20

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Solution

The fourth proportional to 871.72, 1,308.18 and 641.20 is: 962.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    871.72 : 1,308.18 = 641.20 : x
  2. Step 2: Convert to fraction form
    871.72/1,308.18 = 641.20/x
  3. Step 3: Cross multiply
    871.72x = 1,308.18 × 641.20
  4. Step 4: Simplify right side
    871.72x = 838,805.02
  5. Step 5: Solve for x
    x = 838,805.02/871.72
  6. Step 6: Final answer
    x = 962.24

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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.