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Finding the Fourth Proportional to 390.47, 585.53 and 143.68

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Solution

The fourth proportional to 390.47, 585.53 and 143.68 is: 215.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.47 : 585.53 = 143.68 : x
  2. Step 2: Convert to fraction form
    390.47/585.53 = 143.68/x
  3. Step 3: Cross multiply
    390.47x = 585.53 × 143.68
  4. Step 4: Simplify right side
    390.47x = 84,126.02
  5. Step 5: Solve for x
    x = 84,126.02/390.47
  6. Step 6: Final answer
    x = 215.45

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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.