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Finding the Fourth Proportional to 861.64, 1,293.26 and 428.82

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Solution

The fourth proportional to 861.64, 1,293.26 and 428.82 is: 643.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.64 : 1,293.26 = 428.82 : x
  2. Step 2: Convert to fraction form
    861.64/1,293.26 = 428.82/x
  3. Step 3: Cross multiply
    861.64x = 1,293.26 × 428.82
  4. Step 4: Simplify right side
    861.64x = 554,575.75
  5. Step 5: Solve for x
    x = 554,575.75/861.64
  6. Step 6: Final answer
    x = 643.63

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Double scale
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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.