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Finding the Fourth Proportional to 318.72, 439.20 and 215.36

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Solution

The fourth proportional to 318.72, 439.20 and 215.36 is: 296.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.72 : 439.20 = 215.36 : x
  2. Step 2: Convert to fraction form
    318.72/439.20 = 215.36/x
  3. Step 3: Cross multiply
    318.72x = 439.20 × 215.36
  4. Step 4: Simplify right side
    318.72x = 94,586.11
  5. Step 5: Solve for x
    x = 94,586.11/318.72
  6. Step 6: Final answer
    x = 296.77

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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.