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Finding the Fourth Proportional to 853.46, 1,280.28 and 420.74

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Solution

The fourth proportional to 853.46, 1,280.28 and 420.74 is: 631.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.46 : 1,280.28 = 420.74 : x
  2. Step 2: Convert to fraction form
    853.46/1,280.28 = 420.74/x
  3. Step 3: Cross multiply
    853.46x = 1,280.28 × 420.74
  4. Step 4: Simplify right side
    853.46x = 538,665.01
  5. Step 5: Solve for x
    x = 538,665.01/853.46
  6. Step 6: Final answer
    x = 631.15

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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.