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Finding the Fourth Proportional to 390.62, 586.98 and 217.40

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Solution

The fourth proportional to 390.62, 586.98 and 217.40 is: 326.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.62 : 586.98 = 217.40 : x
  2. Step 2: Convert to fraction form
    390.62/586.98 = 217.40/x
  3. Step 3: Cross multiply
    390.62x = 586.98 × 217.40
  4. Step 4: Simplify right side
    390.62x = 127,609.45
  5. Step 5: Solve for x
    x = 127,609.45/390.62
  6. Step 6: Final answer
    x = 326.68

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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.