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Finding the Fourth Proportional to 390.88, 585.84 and 198.40

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Solution

The fourth proportional to 390.88, 585.84 and 198.40 is: 297.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.88 : 585.84 = 198.40 : x
  2. Step 2: Convert to fraction form
    390.88/585.84 = 198.40/x
  3. Step 3: Cross multiply
    390.88x = 585.84 × 198.40
  4. Step 4: Simplify right side
    390.88x = 116,230.66
  5. Step 5: Solve for x
    x = 116,230.66/390.88
  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.