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Finding the Fourth Proportional to 285.72, 393.84 and 215.70

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Solution

The fourth proportional to 285.72, 393.84 and 215.70 is: 297.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.72 : 393.84 = 215.70 : x
  2. Step 2: Convert to fraction form
    285.72/393.84 = 215.70/x
  3. Step 3: Cross multiply
    285.72x = 393.84 × 215.70
  4. Step 4: Simplify right side
    285.72x = 84,951.29
  5. Step 5: Solve for x
    x = 84,951.29/285.72
  6. Step 6: Final answer
    x = 297.32

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.