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Finding the Fourth Proportional to 390.35, 585.34 and 143.55

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Solution

The fourth proportional to 390.35, 585.34 and 143.55 is: 215.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.35 : 585.34 = 143.55 : x
  2. Step 2: Convert to fraction form
    390.35/585.34 = 143.55/x
  3. Step 3: Cross multiply
    390.35x = 585.34 × 143.55
  4. Step 4: Simplify right side
    390.35x = 84,025.20
  5. Step 5: Solve for x
    x = 84,025.20/390.35
  6. Step 6: Final answer
    x = 215.25

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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.