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Finding the Fourth Proportional to 865.58, 1,298.90 and 317.70

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Solution

The fourth proportional to 865.58, 1,298.90 and 317.70 is: 476.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.58 : 1,298.90 = 317.70 : x
  2. Step 2: Convert to fraction form
    865.58/1,298.90 = 317.70/x
  3. Step 3: Cross multiply
    865.58x = 1,298.90 × 317.70
  4. Step 4: Simplify right side
    865.58x = 412,661.32
  5. Step 5: Solve for x
    x = 412,661.32/865.58
  6. Step 6: Final answer
    x = 476.75

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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.