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Finding the Fourth Proportional to 853.69, 1,280.55 and 638.63

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Solution

The fourth proportional to 853.69, 1,280.55 and 638.63 is: 957.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.69 : 1,280.55 = 638.63 : x
  2. Step 2: Convert to fraction form
    853.69/1,280.55 = 638.63/x
  3. Step 3: Cross multiply
    853.69x = 1,280.55 × 638.63
  4. Step 4: Simplify right side
    853.69x = 817,797.65
  5. Step 5: Solve for x
    x = 817,797.65/853.69
  6. Step 6: Final answer
    x = 957.96

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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.