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Finding the Fourth Proportional to 390.87, 586.35 and 171.45

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Solution

The fourth proportional to 390.87, 586.35 and 171.45 is: 257.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.87 : 586.35 = 171.45 : x
  2. Step 2: Convert to fraction form
    390.87/586.35 = 171.45/x
  3. Step 3: Cross multiply
    390.87x = 586.35 × 171.45
  4. Step 4: Simplify right side
    390.87x = 100,529.71
  5. Step 5: Solve for x
    x = 100,529.71/390.87
  6. Step 6: Final answer
    x = 257.19

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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.