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Finding the Fourth Proportional to 390.82, 587.47 and 385.18

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Solution

The fourth proportional to 390.82, 587.47 and 385.18 is: 578.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.82 : 587.47 = 385.18 : x
  2. Step 2: Convert to fraction form
    390.82/587.47 = 385.18/x
  3. Step 3: Cross multiply
    390.82x = 587.47 × 385.18
  4. Step 4: Simplify right side
    390.82x = 226,281.69
  5. Step 5: Solve for x
    x = 226,281.69/390.82
  6. Step 6: Final answer
    x = 578.99

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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.