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Finding the Fourth Proportional to 515.38, 710.49 and 391.45

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Solution

The fourth proportional to 515.38, 710.49 and 391.45 is: 539.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    515.38 : 710.49 = 391.45 : x
  2. Step 2: Convert to fraction form
    515.38/710.49 = 391.45/x
  3. Step 3: Cross multiply
    515.38x = 710.49 × 391.45
  4. Step 4: Simplify right side
    515.38x = 278,121.31
  5. Step 5: Solve for x
    x = 278,121.31/515.38
  6. Step 6: Final answer
    x = 539.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.