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Finding the Fourth Proportional to 636.50, 878.30 and 387.70

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Solution

The fourth proportional to 636.50, 878.30 and 387.70 is: 534.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    636.50 : 878.30 = 387.70 : x
  2. Step 2: Convert to fraction form
    636.50/878.30 = 387.70/x
  3. Step 3: Cross multiply
    636.50x = 878.30 × 387.70
  4. Step 4: Simplify right side
    636.50x = 340,516.91
  5. Step 5: Solve for x
    x = 340,516.91/636.50
  6. Step 6: Final answer
    x = 534.98

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.