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Finding the Fourth Proportional to 390.60, 538.81 and 285.52

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Solution

The fourth proportional to 390.60, 538.81 and 285.52 is: 393.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.60 : 538.81 = 285.52 : x
  2. Step 2: Convert to fraction form
    390.60/538.81 = 285.52/x
  3. Step 3: Cross multiply
    390.60x = 538.81 × 285.52
  4. Step 4: Simplify right side
    390.60x = 153,841.03
  5. Step 5: Solve for x
    x = 153,841.03/390.60
  6. Step 6: Final answer
    x = 393.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.