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Finding the Fourth Proportional to 390.79, 586.09 and 147.18

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Solution

The fourth proportional to 390.79, 586.09 and 147.18 is: 220.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.79 : 586.09 = 147.18 : x
  2. Step 2: Convert to fraction form
    390.79/586.09 = 147.18/x
  3. Step 3: Cross multiply
    390.79x = 586.09 × 147.18
  4. Step 4: Simplify right side
    390.79x = 86,260.73
  5. Step 5: Solve for x
    x = 86,260.73/390.79
  6. Step 6: Final answer
    x = 220.73

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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.