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Finding the Fourth Proportional to 397.65, 543.89 and 391.28

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Solution

The fourth proportional to 397.65, 543.89 and 391.28 is: 535.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    397.65 : 543.89 = 391.28 : x
  2. Step 2: Convert to fraction form
    397.65/543.89 = 391.28/x
  3. Step 3: Cross multiply
    397.65x = 543.89 × 391.28
  4. Step 4: Simplify right side
    397.65x = 212,808.60
  5. Step 5: Solve for x
    x = 212,808.60/397.65
  6. Step 6: Final answer
    x = 535.17

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.