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Finding the Fourth Proportional to 390.76, 585.78 and 171.16

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Solution

The fourth proportional to 390.76, 585.78 and 171.16 is: 256.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.76 : 585.78 = 171.16 : x
  2. Step 2: Convert to fraction form
    390.76/585.78 = 171.16/x
  3. Step 3: Cross multiply
    390.76x = 585.78 × 171.16
  4. Step 4: Simplify right side
    390.76x = 100,262.10
  5. Step 5: Solve for x
    x = 100,262.10/390.76
  6. Step 6: Final answer
    x = 256.58

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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.