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Finding the Fourth Proportional to 412.80, 619.20 and 339.90

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Solution

The fourth proportional to 412.80, 619.20 and 339.90 is: 509.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    412.80 : 619.20 = 339.90 : x
  2. Step 2: Convert to fraction form
    412.80/619.20 = 339.90/x
  3. Step 3: Cross multiply
    412.80x = 619.20 × 339.90
  4. Step 4: Simplify right side
    412.80x = 210,466.08
  5. Step 5: Solve for x
    x = 210,466.08/412.80
  6. Step 6: Final answer
    x = 509.85

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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.