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Finding the Fourth Proportional to 865.40, 1,297.08 and 431.66

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Solution

The fourth proportional to 865.40, 1,297.08 and 431.66 is: 646.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.40 : 1,297.08 = 431.66 : x
  2. Step 2: Convert to fraction form
    865.40/1,297.08 = 431.66/x
  3. Step 3: Cross multiply
    865.40x = 1,297.08 × 431.66
  4. Step 4: Simplify right side
    865.40x = 559,897.55
  5. Step 5: Solve for x
    x = 559,897.55/865.40
  6. Step 6: Final answer
    x = 646.98

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1.5x scale

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.