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Finding the Fourth Proportional to 865.61, 1,298.48 and 317.79

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Solution

The fourth proportional to 865.61, 1,298.48 and 317.79 is: 476.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.61 : 1,298.48 = 317.79 : x
  2. Step 2: Convert to fraction form
    865.61/1,298.48 = 317.79/x
  3. Step 3: Cross multiply
    865.61x = 1,298.48 × 317.79
  4. Step 4: Simplify right side
    865.61x = 412,642.37
  5. Step 5: Solve for x
    x = 412,642.37/865.61
  6. Step 6: Final answer
    x = 476.71

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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.