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Finding the Fourth Proportional to 390.39, 585.85 and 198.15

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Solution

The fourth proportional to 390.39, 585.85 and 198.15 is: 297.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.39 : 585.85 = 198.15 : x
  2. Step 2: Convert to fraction form
    390.39/585.85 = 198.15/x
  3. Step 3: Cross multiply
    390.39x = 585.85 × 198.15
  4. Step 4: Simplify right side
    390.39x = 116,086.18
  5. Step 5: Solve for x
    x = 116,086.18/390.39
  6. Step 6: Final answer
    x = 297.36

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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.