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Finding the Fourth Proportional to 390.40, 584.40 and 347.20

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Solution

The fourth proportional to 390.40, 584.40 and 347.20 is: 519.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.40 : 584.40 = 347.20 : x
  2. Step 2: Convert to fraction form
    390.40/584.40 = 347.20/x
  3. Step 3: Cross multiply
    390.40x = 584.40 × 347.20
  4. Step 4: Simplify right side
    390.40x = 202,903.68
  5. Step 5: Solve for x
    x = 202,903.68/390.40
  6. Step 6: Final answer
    x = 519.73

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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.