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Finding the Fourth Proportional to 390.75, 586.35 and 198.39

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Solution

The fourth proportional to 390.75, 586.35 and 198.39 is: 297.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.75 : 586.35 = 198.39 : x
  2. Step 2: Convert to fraction form
    390.75/586.35 = 198.39/x
  3. Step 3: Cross multiply
    390.75x = 586.35 × 198.39
  4. Step 4: Simplify right side
    390.75x = 116,325.98
  5. Step 5: Solve for x
    x = 116,325.98/390.75
  6. Step 6: Final answer
    x = 297.70

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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.