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Finding the Fourth Proportional to 412.80, 618.48 and 391.20

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Solution

The fourth proportional to 412.80, 618.48 and 391.20 is: 586.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    412.80 : 618.48 = 391.20 : x
  2. Step 2: Convert to fraction form
    412.80/618.48 = 391.20/x
  3. Step 3: Cross multiply
    412.80x = 618.48 × 391.20
  4. Step 4: Simplify right side
    412.80x = 241,949.38
  5. Step 5: Solve for x
    x = 241,949.38/412.80
  6. Step 6: Final answer
    x = 586.12

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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.