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Finding the Fourth Proportional to 451.80, 679.20 and 392.40

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Solution

The fourth proportional to 451.80, 679.20 and 392.40 is: 589.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    451.80 : 679.20 = 392.40 : x
  2. Step 2: Convert to fraction form
    451.80/679.20 = 392.40/x
  3. Step 3: Cross multiply
    451.80x = 679.20 × 392.40
  4. Step 4: Simplify right side
    451.80x = 266,518.08
  5. Step 5: Solve for x
    x = 266,518.08/451.80
  6. Step 6: Final answer
    x = 589.90

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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.