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Finding the Fourth Proportional to 864.86, 1,297.28 and 215.60

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Solution

The fourth proportional to 864.86, 1,297.28 and 215.60 is: 323.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.86 : 1,297.28 = 215.60 : x
  2. Step 2: Convert to fraction form
    864.86/1,297.28 = 215.60/x
  3. Step 3: Cross multiply
    864.86x = 1,297.28 × 215.60
  4. Step 4: Simplify right side
    864.86x = 279,693.57
  5. Step 5: Solve for x
    x = 279,693.57/864.86
  6. Step 6: Final answer
    x = 323.40

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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.