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Finding the Fourth Proportional to 638.40, 955.20 and 580.80

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Solution

The fourth proportional to 638.40, 955.20 and 580.80 is: 869.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.40 : 955.20 = 580.80 : x
  2. Step 2: Convert to fraction form
    638.40/955.20 = 580.80/x
  3. Step 3: Cross multiply
    638.40x = 955.20 × 580.80
  4. Step 4: Simplify right side
    638.40x = 554,780.16
  5. Step 5: Solve for x
    x = 554,780.16/638.40
  6. Step 6: Final answer
    x = 869.02

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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.